JP3702011B2 - Fuel cell and operation method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell including a catalytic combustor that burns unreacted fuel gas from a fuel cell main body.
[0002]
[Prior art]
In recent years, portable fuel cells have been developed as small portable power sources. This portable fuel cell can generate power of several hundred watts, and emits less air pollutants compared to a portable power source that generates electricity by driving a generator using a conventional engine. It is excellent in that there is little occurrence.
[0003]
Generally, a portable fuel cell has a fuel cell body in which phosphoric acid type power generation cells are stacked, and an air supply fan that feeds air into the fuel cell, a hydrogen storage alloy tank that feeds hydrogen as fuel gas, etc. In the operation, power generation is performed using air fed by an air supply fan and hydrogen supplied from a hydrogen supply source.
[0004]
In such a portable fuel cell, it is considered that it can be operated with a simple configuration as much as possible, and the fuel cell body is cooled by air sent from the air supply fan to the fuel cell body. A device has been devised in which high-temperature exhaust air discharged from the main body is used for heating the hydrogen storage alloy tank.
[0005]
By the way, since unreacted fuel gas is discharged from the fuel cell main body, the portable fuel cell is usually provided with a catalytic combustor for processing this unreacted hydrogen. This catalytic combustor is provided with a catalyst layer in which a platinum catalyst or the like is held, and a catalytic combustion is conducted by introducing a mixture of unreacted hydrogen and air into the catalyst layer.
[0006]
Therefore, in order to operate the catalytic combustor, it is necessary to send air into it, but if the amount of air fed in is too small, the temperature will rise too much and the deterioration of the catalyst will be accelerated and the performance of the catalytic combustor will be reduced. Problem arises. Therefore, in a portable fuel cell, it is conceivable to install a small combustor fan and feed a necessary amount of air to the catalyst combustor separately from the fan that feeds air to the fuel cell body.
[0007]
[Problems to be solved by the invention]
However, installing such a separate combustor fan is not preferable from the viewpoint of simplifying the overall configuration of the portable fuel cell as much as possible.
Therefore, it can be said that simplifying the configuration of the portable fuel cell while ensuring the performance of the catalytic combustor is one of the problems in designing the portable fuel cell.
[0008]
In addition, such a problem is not limited to portable fuel cells, but may be present in the same manner as long as the fuel cell includes a catalytic combustor that processes unreacted fuel gas discharged from the fuel cell body.
In view of such problems, the present invention sends air into a fuel cell body by devising a design of a fuel cell including a catalytic combustor that processes unreacted fuel gas discharged from the fuel cell body. It aims at providing the fuel cell which can ensure the performance of a catalyst combustor, and the operating method, without providing a fan different from a fan.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention is directed to a fuel cell main body that generates power using air and fuel gas supplied from a fuel supply source, and the fuel cell main body via a first flow passage. A fuel cell comprising a blower fan for blowing air, and a catalytic combustor for catalytic combustion of unreacted fuel gas discharged from the battery body and oxygen taken in from the oxygen supply means through the second flow passage In the present invention, the blower fan and the oxygen supply means are shared, and the first flow path and the second flow path are provided in parallel.
[0010]
With such a configuration, the catalytic combustor can perform catalytic combustion by taking in combustion air from the air flow path from the blower fan without installing a separate fan as in the prior art. Moreover, since the catalyst combustor is air-cooled in contact with sufficient air by being interposed in the air flow path from the blower fan, catalyst deterioration due to high temperature can be avoided.
[0011]
The invention according to claim 2 is provided on the upstream side of the fuel cell main body with respect to the invention according to claim 1, and blows air from the combustion gas discharged from the catalyst combustor and the blower fan through the first flow passage. It is characterized by comprising a confluence portion where the air that has been collected merges.
[0012]
In this case, air heated to high temperature by catalytic combustion of unreacted fuel gas (hereinafter referred to as combustion air) is returned to the passage of air sent from the catalytic combustor to the fuel cell body. Therefore, there is an effect of reducing the temperature difference between the air inlet side and the outlet side of the fuel cell main body.
[0013]
The invention described in claim 3 is the operation method of the invention described in claim 1, characterized in that the catalytic combustor is air-cooled by air blown from a blower fan.
[0014]
The invention described in claim 4 is the operation method of the invention described in claim 2, characterized in that the temperature of air blown to the fuel cell body is raised by the combustion gas discharged from the catalytic combustor.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(Example 1)
[Description of portable fuel cell configuration]
FIG. 1 is a perspective view of a portable fuel cell according to the present embodiment. For the sake of explanation, the direction of the arrow A in FIG. 1 is the forward direction, and the horizontal direction orthogonal to the arrow A is the lateral direction.
[0016]
This portable fuel cell includes a phosphoric acid type fuel cell main body 2 that generates electricity by receiving supply of hydrogen and air in a portable case 1 and hydrogen that supplies stored hydrogen to the fuel cell main body 2. The storage alloy tank 6, the air supply fan 8 for supplying air to the fuel cell main body 2, the catalyst combustor 10 for treating unreacted hydrogen discharged from the fuel cell main body 2, and the voltage of the electric power supplied to the outside are constant. A DC-DC converter 20 that controls the above and a control device 21 for controlling the operations of these units are housed.
[0017]
The case 1 is formed of a light metal such as duralumin in a rectangular parallelepiped shape, and an air intake port 41 and an air discharge port 42 are provided on the upper portion thereof. In FIG. 1, in order to show the internal structure of the portable fuel cell, the upper surface, the front surface, and one side surface of the case 1 are drawn through.
The fuel cell main body 2 includes a rectangular parallelepiped battery stack 3, a distribution manifold 4 that covers the upper surface of the battery stack 3 and distributes hydrogen to the battery stack 3, and covers the lower surface of the battery stack 3 to remove unreacted hydrogen from the battery stack 3. It is comprised from the collection | recovery manifold 5 to collect | recover, and is installed in the center lower part of the case 1. FIG.
[0018]
The configuration of the battery stack 3 is not shown, but a predetermined number (for example, 30) of rectangular phosphoric acid power generation cells are stacked in a lateral direction via bipolar plates, and both ends of the stacked body are end plates. It is configured to be tightened.
In the fuel cell main body 2, the hydrogen gas supplied to the distribution manifold 4 is supplied to the power generation cell while flowing downward in the battery stack 3, and unreacted hydrogen is recovered by the recovery manifold 5. On the other hand, the air supplied to the front surface of the battery stack 3 is supplied to the power generation cells while flowing backward in the battery stack 3 and air-cools the fuel cell main body 2. Discharged from.
[0019]
Inside the case 1, partition plates 31, 32, and 33 are provided along the rear surface, upper surface, and front surface of the fuel cell main body 2.
The interior of the case 1 is partitioned forward and backward by a partition plate 31, and a rear space 34 is formed behind the partition. The front space of the partition plate 31 is partitioned vertically by the partition plate 32, an upper space 35 is formed above the partition plate 32, and the lower space is partitioned front and rear by the partition plate 33. 36 is formed. Note that portions of the partition plate 31 and the partition plate 33 facing the battery stack 3 are opened so that air entering and exiting the battery stack 3 can flow.
[0020]
The hydrogen storage alloy tank 6 is connected to a plurality of (5 in the illustrated example) hydrogen storage alloy tanks 6 a filled with a hydrogen storage alloy and can be mounted in the rear space 34. The hydrogen storage alloy tank 6 and the distribution manifold 4 are connected by a hydrogen introduction pipe (not shown) so that hydrogen is supplied to the distribution manifold 4.
[0021]
Between the fuel cell main body 2 and the hydrogen storage alloy tank 6, a damper 7 (not shown in FIG. 1, refer to FIG. 2) for adjusting the flow of exhaust air from the fuel cell main body 2 is provided. In the open state of the damper 7, the exhaust air from the fuel cell body 2 hits the hydrogen storage alloy tank 6 to heat it, and in the closed state, the exhaust air is exhausted upward so that the hydrogen storage alloy tank 6 is not heated. It has become. The air discharge port 42 described above is provided above the hydrogen storage alloy tank 6.
[0022]
The air supply fan 8 includes an air inlet 8 a at the center and an air outlet 8 b on the lower side, and is installed in the upper space 35 above the front space 36. In addition, the part with respect to the ventilation port 8b of the partition plate 32 is opened, and the air from the ventilation port 8b can pass the partition plate 32 here.
The catalytic combustor 10 has a rectangular parallelepiped exterior plate 11 whose upper and lower surfaces are open, a rod-shaped hydrogen supply nozzle 12 inserted into an upper space in the exterior plate 11, and a lower space inside the exterior plate 11. And is fixed to the front of the front space 36 by a support plate 37 installed below the partition plate 32 in the front space 36.
[0023]
The support plate 37 is provided with an opening 37a and an opening 37b so that air from above is distributed to the inside and outside of the catalyst combustor 10 at an appropriate ratio and flows downward. . Although not shown, a hydrogen introduction pipe for introducing unreacted hydrogen is provided between the recovery manifold 5 and the hydrogen supply nozzle 12.
The catalyst layer 13 is formed by holding a platinum catalyst on a honeycomb-shaped holding body, and catalytically combusts a mixture of unreacted hydrogen and air passing therethrough.
[0024]
In such a catalytic combustor 10, unreacted hydrogen from the recovery manifold 5 is catalytically combusted using air taken in from the upper surface, and high-temperature combustion gas is discharged from the lower surface.
The DC-DC converter 20 and the control device 21 are installed so as to overlap in the upper space 35. In addition, the air intake 41 mentioned above is opened in the position along the DC-DC converter 20 and the control apparatus 21, and these can be efficiently air-cooled now. Although not shown in the figure, a startup heater that heats the air sent from the air supply fan 8 to the fuel cell main body 2 during startup is installed in the front space 36.
[0025]
[Description of operation during operation of portable fuel cell]
FIG. 2A is a schematic cross-sectional view of the portable fuel cell shown in FIG. 1 taken along line XX, in which the air flow is indicated by white arrows. Moreover, FIG.2 (b) is a flowchart which shows the flow of hydrogen and air. The operation during operation of the portable fuel cell having the above configuration will be described with reference to FIGS.
[0026]
During operation, the control device 21 opens and closes the damper 7 based on the pressure of the hydrogen storage alloy tank 6 to adjust the heating of the hydrogen storage alloy tank 6 (that is, when the pressure is lower than a predetermined value, it opens and is higher than the predetermined value). Close when). Thereby, the internal pressure of the hydrogen storage alloy tank 6 is controlled to an appropriate value, and hydrogen is stably supplied to the fuel cell main body 2.
The air supply fan 8 is driven by using a part of the electric power generated by the fuel cell main body 2, but the control device 21 controls the air supply fan 8 based on the temperature of the fuel cell main body 2. Therefore, the fuel cell main body 2 is kept at a predetermined operating temperature.
[0027]
Hydrogen supplied from the hydrogen storage alloy tank 6 to the fuel cell main body 2 is supplied to power generation while flowing downward in the battery stack 3, and then unreacted hydrogen is introduced into the catalytic combustor 10.
The air taken in from the outside by the air supply fan 8 and fed into the front space 36 is distributed to the opening 37a and the opening 37b. The air that has passed through the opening 37a passes through the catalytic combustor 10 and is mixed with unreacted hydrogen and used for combustion. The combustion air is discharged from the catalytic combustor 10 and merges with the air that has passed through the opening 37b. Then, it flows into the fuel cell main body 2.
[0028]
Here, the catalytic combustor 10 is air-cooled by the air passing through the inside thereof and the air passing through the opening 37b and flowing outside the exterior plate 11, but the air supply fan 8 has a sufficiently large air flow rate. The catalyst combustor 10 is not heated to cause catalyst deterioration.
The air supplied to the fuel cell main body 2 is supplied to the power generation while flowing backward in the cell stack 3 and cools the fuel cell main body 2 in the air. Here, in the fuel cell main body 2, there is a tendency for the temperature distribution to be non-uniform such that the temperature at the inlet side of the air is lower than that at the outlet side. Since high-temperature combustion air is mixed, there is an effect of suppressing the non-uniformity of the temperature distribution.
[0029]
Thus, the electric power generated by the fuel cell main body 2 under the supply of air and hydrogen under the control of the control device 21 is converted into a voltage by the DC-DC converter 20 and supplied to the outside.
The DC-DC converter 20 and the control device 21 gradually increase in temperature due to heat generation during operation, but are always exposed to air from the outside, so that an excessive temperature increase is prevented.
[0030]
(Example 2)
FIG. 3A is a schematic cross-sectional view showing the configuration of the portable fuel cell of the present embodiment, in which the air flow is indicated by white arrows. FIG. 3B is a flowchart showing the flow of hydrogen and air in the portable fuel cell of this example. For the sake of explanation, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.
[0031]
The portable fuel cell according to the present embodiment has the same configuration as the portable fuel cell according to the first embodiment, but is provided with a duct 50 that sends combustion air discharged from the lower surface of the catalytic combustor 10 to the rear space 34. .
The duct 50 includes a vertical duct portion 51 extending downward from the lower surface of the catalytic combustor 10 and a horizontal duct portion 52 extending rearward from the lower end thereof. The horizontal duct portion 52 has a rectangular tube shape. From the front space 36, the fuel cell body 2 is provided over the rear space 34 through the gap between the side surface on one side of the fuel cell main body 2 and the case 1.
[0032]
During the operation of the portable fuel cell according to the present embodiment, the high-temperature combustion air discharged from the catalytic combustor 10 does not flow into the fuel cell main body 2 but flows into the lower portion of the rear space 34 through the duct 50. The air is mixed with the exhausted air discharged from the battery body 2, rises in the rear space 34, and is discharged to the outside through the air discharge port 42.
Also in this embodiment, the effect of the catalyst combustor 10 being sufficiently air-cooled by the air passing through the inside and the air flowing outside the exterior plate 11 is the same as that in the first embodiment.
[0033]
In the present embodiment, there is no effect of suppressing the non-uniformity of the temperature distribution of the fuel cell main body 2 as in the first embodiment. By increasing the generation of hydrogen from the hydrogen-absorbing alloy tank 6 by heating it against the above, the start-up time can be shortened.
( Reference Example 1 )
FIG. 4A is a schematic cross-sectional view showing the configuration of the portable fuel cell of this reference example, in which the air flow is indicated by white arrows. FIG. 4B is a flowchart showing the flow of hydrogen and air in the portable fuel cell of this reference example. For the sake of explanation, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.
[0034]
The portable fuel cell of this reference example has the same configuration as the portable fuel cell of Example 1, but the catalytic combustor 10 is provided in the upper part of the rear space 34, and the exhaust air discharged from the fuel cell main body 2 is All are configured to pass through the catalytic combustor 10.
In this reference example, since air flows from the bottom to the top in the catalytic combustor 10, the vertical direction of the catalytic combustor 10 is opposite to that in the first embodiment. Further, the hydrogen storage alloy tank 6 is provided below the catalytic combustor 10.
[0035]
Also in this reference example, the catalytic combustor 10 is sufficiently air-cooled by the air passing through the inside thereof.
In the case of a phosphoric acid type fuel cell, impurities such as organic substances are contained in the exhaust air of the fuel cell main body during operation, and the impurities are mixed with the exhaust air from the fuel cell main body at the start-up when the temperature is low. Although there is a problem of being discharged, during the operation of the portable fuel cell of this reference example, even if such an impurity is discharged from the fuel cell main body 2, the impurity is treated in the catalytic combustor 10 by catalytic combustion. Is done. Therefore, it is possible to prevent the impurities from being discharged during startup.
[0036]
( Reference Example 2 )
FIG. 5A is a schematic cross-sectional view showing the configuration of the portable fuel cell of this reference example, and the air flow is indicated by white arrows in the drawing. FIG. 5B is a flowchart showing the flow of hydrogen and air in the portable fuel cell of this reference example. For the sake of explanation, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.
[0037]
Portable fuel cell of the present reference example is the same configuration as the portable fuel cell of Example 1, so that the exhausted air from the fuel cell main body 2 in Reference Example 1 passes through all the catalytic combustor 10 In contrast, in this reference example, only a part of the exhaust air from the fuel cell main body 2 passes through the catalytic combustor 10.
In this reference example, a partition plate 38 that divides the exhaust air from the fuel cell main body 2 into upper and lower portions is provided in the rear space 34. The catalyst combustor 10 is provided on the partition plate 38, and air flows into the catalyst combustor 10 from the lower side of the partition plate 38.
[0038]
With such a configuration, of the exhausted air discharged from the fuel cell main body 2, the air discharged to the upper side of the partition plate 38 is discharged outside without passing through the catalytic combustor 10, and the lower side of the partition plate 38. Is discharged through the catalytic combustor 10 to the outside.
Also in this reference example, the catalytic combustor 10 is sufficiently air-cooled by the air passing through the inside thereof and the air flowing outside the exterior plate 11.
[0039]
Further, by adjusting the position of the partition plate 38, the ratio between the amount of exhaust air flowing into the catalytic combustor 10 and the amount of exhaust air directly discharged to the outside can be adjusted. Further, since the exhausted air discharged to the lower side of the partition plate 38 is catalytically burned with impurities in the catalytic combustor 10, the deodorizing effect of the exhausted air at the start can be obtained correspondingly.
[0040]
In Examples 1 and 2 and Reference Examples 1 and 2 , an example of a portable fuel cell provided with a hydrogen storage alloy tank has been shown. However, a hydrogen storage alloy tank is not provided, for example, hydrogen from an external hydrogen cylinder. The same can be applied to a portable fuel cell that operates by being supplied. Further, the fuel gas is not limited to hydrogen, and any fuel gas rich in hydrogen can be similarly implemented.
[0041]
Moreover, although the example of the portable fuel cell was shown in the said Example 1 , 2 and the reference examples 1 and 2 , this invention is a catalyst combustion which processes the fan which sends air into a fuel cell main body, and unreacted fuel gas If it is a fuel cell provided with a vessel, it can be similarly implemented.
[0042]
【The invention's effect】
According to the first to fourth aspects of the present invention, the catalytic combustor can perform catalytic combustion with the air taken in from the air flow path from the blower fan that feeds air into the fuel cell main body, and the catalyst combustor can be air-cooled. Therefore, the performance of the catalytic combustor can be ensured without installing a separate fan as in the prior art, and the configuration of the fuel cell can be simplified.
[0043]
According to the second and fourth aspects of the invention, the effect of reducing the temperature difference between the air inlet side and the outlet side of the fuel cell main body contributes to the improvement of the cell characteristics and the long life of the fuel cell main body. can do.
[Brief description of the drawings]
1 is a perspective view of a portable fuel cell according to Embodiment 1. FIG.
FIG. 2 is a schematic cross-sectional view of the portable fuel cell shown in FIG. 1 taken along line XX, and a flow diagram showing the flow of hydrogen and air in the portable fuel cell.
FIG. 3 is a schematic cross-sectional view showing the configuration of a portable fuel cell of Example 2, and a flow diagram showing the flow of hydrogen and air in the portable fuel cell.
4 is a schematic cross-sectional view showing a configuration of a portable fuel cell of Reference Example 1 , and a flow diagram showing the flow of hydrogen and air in the portable fuel cell. FIG.
FIG. 5 is a schematic cross-sectional view showing the configuration of a portable fuel cell of Reference Example 2 , and a flow diagram showing the flow of hydrogen and air in the portable fuel cell.
[Explanation of symbols]
2 Fuel Cell Body 6 Hydrogen Storage Alloy Tank 8 Air Supply Fan 10 Catalytic Combustor 37 Support Plate 50 Duct

Claims (4)

A fuel cell main body that generates power using air and fuel gas supplied from a fuel supply source, a blower fan that blows air to the fuel cell main body through a first flow path, and exhausted from the battery main body A fuel cell comprising a catalytic combustor that catalytically combusts unreacted fuel gas and oxygen taken in from the oxygen supply means through the second flow path,
A fuel cell characterized in that the blower fan and the oxygen supply means are shared, and the first flow path and the second flow path are provided in parallel. The fuel cell according to claim 1, wherein
Provided on the upstream side of the fuel cell main body is provided with a merging portion where the combustion gas discharged from the catalytic combustor and the air blown from the blower fan through the first flow passage merge. A fuel cell. The fuel cell according to claim 1, wherein
A method of operating a fuel cell, wherein the catalyst combustor is air-cooled by air blown from the blower fan. The fuel cell according to claim 2, wherein
A method of operating a fuel cell, wherein the temperature of air blown to the fuel cell main body is raised by combustion gas discharged from the catalytic combustor.

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