JP2004192985A - Separator for fuel cell, and fuel cell using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the total power generation efficiency of a fuel cell by allowing oxidizer gas to be efficiently introduced. <P>SOLUTION: The separator for a fuel cell has a fuel gas passage on one-side surface, and an oxidizer gas passage on the other-side surface. The oxidizer gas passage is reduced in passage resistance by expanding a passage cross-sectional area on the entrance side of the oxidizer gas. Specifically, a plurality of grooves are arranged and formed as the oxidizer gas passages in parallel with one another by interlaying ribs, and the respective ribs are so formed as to gradually reduce their widths on the entrance side of the oxidizer gas. The bottom surface of each groove for the oxidizer gas passage is formed into a tilting surface directed toward the oxidizer gas entrance on the oxidizer gas entrance side. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell separator having an oxidant gas flow path formed thereon, and further relates to a fuel cell using the same.
[0002]
[Prior art]
A fuel cell is a power generation element that generates power by electrochemically reacting, for example, hydrogen gas (fuel gas) and oxygen (oxidant gas) contained in air. Fuel cells have attracted attention in recent years as power generating elements that do not pollute the environment because the product generated by power generation is water.For example, attempts have been made to use them as drive power sources for driving automobiles. I have.
[0003]
Further, fuel cells are being actively developed as a drive power source for not only the above-described drive power source for driving a car but also a portable electronic device such as a notebook personal computer, a mobile phone, and a PDA. In such a fuel cell, it is important to be able to stably output required electric power and to have a portable size and weight, and various technologies have been actively developed to meet such demands. I have.
[0004]
Fuel cells are classified into various types according to differences in electrolytes and the like. As a typical example, a fuel cell using a solid polymer electrolyte as an electrolyte is known. The polymer electrolyte fuel cell is promising for, for example, the above applications because it can be reduced in cost, can be easily reduced in size and weight, and has a high output density in terms of battery performance.
[0005]
By the way, in the fuel cell as described above, how to efficiently supply hydrogen gas, which is a fuel gas, and air, which is an oxidant gas, to the fuel electrode and the oxidant electrode is a factor in improving the overall power generation efficiency of the fuel cell. Is important. Here, hydrogen, which is a fuel gas, is usually supplied under pressure from a high-pressure gas tank, a hydrogen storage cartridge, or the like, so that the supply method does not matter. On the other hand, air which is an oxidizing gas needs to be sent into the oxidizing gas flow path using, for example, a fan or the like.
[0006]
For example, when air is supplied to the fuel cell stack by a fan, which is an auxiliary device for supplying oxidant gas, it is considered that in order to realize efficient supply, it is necessary to increase the air supply, but in this case, Therefore, large power is required to drive the fan. Normally, the fan, which is an auxiliary device for supplying the oxidizing gas, is also driven by the power of the fuel cell, and consuming large power by the fan is not preferable when considering the overall power generation efficiency of the fuel cell. Absent. In addition, a fan having a large blowing capacity is inevitably increased in size, resulting in an increase in the size of a fuel cell incorporating the fan, and lowering the volume output density of the fuel cell. Further, in order to increase the amount of air to be blown, it is necessary to increase the number of rotations of the fan. However, noise generated by the fan also causes a problem.
[0007]
As a technique for efficiently supplying air as an oxidizing gas, a technique described in Patent Document 1 and a technique described in Patent Document 2 are known. However, a special introduction path is required or the shape is restricted. However, none of them are sufficient, and further improvement is desired when considering miniaturization of the fuel cell.
[0008]
[Patent Document 1]
JP 2001-313061 A
[Patent Document 2]
JP 2000-323155 A
[Problems to be solved by the invention]
The present invention has been proposed in view of such conventional circumstances, and a fuel cell separator capable of efficiently taking in an oxidizing gas and improving the overall power generation efficiency of the fuel cell has been proposed. It is another object of the present invention to provide a fuel cell having excellent power generation efficiency. It is another object of the present invention to provide a fuel cell separator and a fuel cell that can be operated quietly without increasing the size.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the fuel cell separator of the present invention has a fuel gas flow path on one surface and an oxidizing gas flow path on the other surface, and the oxidizing gas flow path is The cross-sectional area of the flow path is enlarged on the inlet side of the oxidizing gas to reduce the flow path resistance.
[0012]
Further, the fuel cell of the present invention has a joined body including an ion conductor having ion conductivity and electrodes facing each other with the ion conductor interposed therebetween, and a separator sandwiching the joined body. Having a stack structure in which a body and a separator are stacked, the separator has a fuel gas flow path on one surface, and has an oxidizing gas flow path on the other surface, and the oxidizing gas flow path is The cross-sectional area of the flow path is enlarged on the inlet side of the oxidizing gas to reduce the flow path resistance.
[0013]
In the fuel cell separator of the present invention, in the oxidizing gas flow path, the flow path cross-sectional area on the inlet side of the oxidizing gas is enlarged and the flow path resistance is reduced, so that the oxidizing gas (air) is efficiently removed. Can be taken into account. Therefore, the oxidizing gas is efficiently supplied to the oxidizing electrode even when the driving power of the auxiliary device (for example, a fan) for supplying the oxidizing gas is suppressed. Also, there is no need to increase the size of the auxiliary equipment for supplying the oxidizing gas, and silent operation is realized.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a fuel cell separator and a fuel cell to which the present invention is applied will be described in detail with reference to the drawings.
[0015]
FIG. 1 is an exploded view of a power generation portion of a fuel cell. Usually, a fuel cell has a stack structure, and this stack structure is composed of an electrolyte membrane 1 made of a solid polymer electrolyte membrane, and two electrodes 2 disposed on both sides of the electrolyte membrane so as to sandwich the electrolyte membrane. 3 (a fuel electrode and an oxidizer electrode) and a separator 4 serving as a partition between cells.
[0016]
Here, a solid polymer electrolyte membrane, for example, is used for the electrolyte membrane 1 in consideration of requirements such as high energy density, low cost, and light weight. As the solid polymer electrolyte membrane, for example, a sulfonic acid-based solid polymer electrolyte membrane can be used. As the electrodes 2 and 3, for example, electrodes carrying a catalyst for promoting a power generation reaction are used.
[0017]
The electrolyte membrane 1 is sandwiched between the electrodes 2 and 3, and a power generation cell (unit element) is configured by sandwiching a joined body composed of the electrolyte membrane 1 and the electrodes 2 and 3 between two separators 4.
[0018]
The fuel electrode of the electrodes 2 and 3 is supplied with hydrogen as a fuel, and the supplied hydrogen is dissociated into hydrogen ions and electrons. The hydrogen ions pass through the electrolyte and the electrons pass through an external circuit to supply power. Generate and move to the oxidizer electrode respectively. Oxygen (air), which is an oxidant, is supplied to the oxidant electrode, and oxygen in the supplied air reacts with the hydrogen ions and electrons to generate water.
[0019]
The separator 4 basically has a function as a partition between cells, but also has a function as a current collector, a fuel gas flow path, and an air flow path. Therefore, it is formed of a dense material that does not transmit these gases.
[0020]
A fuel gas flow path for flowing hydrogen as a fuel and an oxidizing gas flow path for flowing air as an oxidizing gas are formed on surfaces of the separator 4 in contact with the electrodes 2 and 3, respectively. . 2 to 5 show plane shapes of surfaces of the separator 4 which are in contact with the electrode 2 or the electrode 3, respectively.
[0021]
FIG. 2 shows the fuel gas flow path 5 formed in the separator 4. The fuel gas flow path 5 is formed of a groove meandering in a so-called meander shape. By supplying hydrogen gas to the fuel gas flow path 5, hydrogen gas is supplied to almost the entire fuel electrode of each power generation cell. Will be.
[0022]
In each separator 4, a fuel supply hole 6 serving as an inlet for hydrogen gas and a fuel discharge hole 7 serving as an outlet for fuel exhaust gas after consumption of hydrogen at the fuel electrode are formed so as to penetrate the separator 4 in the thickness direction. One end of the fuel gas flow path 5 is connected to the fuel supply hole 6 via the inlet 8, and the other end is connected to the fuel discharge hole 7 via the outlet 9. . The fuel supply hole 6 and the fuel discharge hole 7 communicate with each other when the plurality of separators 4 are overlapped, and constitute a fuel supply passage and a fuel discharge passage, respectively.
[0023]
Here, for example, when water condenses and accumulates in the fuel gas flow path 5, it becomes difficult to stably supply the fuel gas, and the water covers the power generation surface of the fuel electrode to suppress the reaction and stabilize the power generation. May be difficult to continue. Therefore, in the present embodiment, the passage resistance of the outlet 9 to the fuel discharge hole 7 is smaller than the passage resistance of the inlet 8 from the fuel supply hole 6.
[0024]
That is, as shown in FIG. 2, one end of the fuel gas flow path 5 is connected to the fuel supply hole 6 through the inlet 8, and the other end is connected to the fuel discharge hole 7 through the outlet 9. Although they are connected, in particular, they are designed so that the flow path resistance of the inlet 8 is smaller than the flow path resistance of the discharge port 9. Specifically, as shown in FIG. 2, the groove width w ₁ of the retraction port 8 is narrower than the groove width w ₂ of the fuel gas flow passage 5, and as shown in FIG. 3 (a) The groove depth d ₁ of the inlet 8 is formed smaller than the groove depth d ₂ of the fuel gas flow path 5. Therefore, the flow passage cross-sectional area of the inlet 8 is smaller than the flow passage cross-sectional area of the fuel gas flow passage 5.
[0025]
Outlet 9, as shown in FIG. 2, which is similar to the previous service entrance 8, the groove width w ₃ is narrower than the groove width w ₂ of the fuel gas channel 5. However, as shown in FIG. 3B, the groove depth d ₃ of the discharge port 9 is larger than the groove depth d _{2 of} the fuel gas flow path 5 and is formed deeper than the fuel gas flow path 5. I have. Therefore, the cross-sectional area of the outlet 9 is larger than the cross-sectional area of the inlet 8.
[0026]
As described above, the cross-sectional area of the outlet 9 is made larger than the cross-sectional area of the inlet 8, and the outlet to the fuel outlet 7 is determined by the flow resistance of the inlet 8 from the fuel supply hole 6. 9 is designed to have a smaller flow path resistance, when water condenses in the fuel gas flow path 5, a pressure difference can be generated between the supply side and the discharge side. The condensed water can be quickly discharged from the fuel gas passage 5 due to the difference.
[0027]
As a technique for increasing the flow path resistance of the fuel gas flow paths 5a and 5b on the fuel gas inlet side, as described above, the groove width of the inlets 8a and 8b is reduced or the groove depth is reduced. In addition to the method of reducing the cross-sectional area of the flow path, a method of performing a surface treatment to reduce the flow path resistance on portions other than the inlets 8a and 8b can be adopted. Examples of the surface treatment include a surface roughening treatment by mechanical processing such as shot peening and a surface roughening treatment by chemical processing such as etching. Further, as the surface treatment, formation of a projection or groove processing may be performed.
[0028]
4 and 5 show the oxidizing gas flow path 10 formed in the separator 4. FIG. The oxidant gas flow path 10 is formed as a groove between the ribs 11 by forming a large number of ribs 11 at predetermined intervals on a surface of the separator 4 in contact with the oxidant electrode (air electrode). Therefore, the oxidizing gas flow path 10 is composed of a plurality of parallel flow paths, and air is sent into these flow paths from one long side of the separator 4 and discharged from the long side opposite to the separator 4. You.
[0029]
At the end on the air inlet side of each oxidizing gas passage 10, an inclined surface 11a (a taper in the left-right direction) is formed at the tip so that the width of each rib 11 is gradually reduced, and the bottom of the groove is formed. There are formed as progressively deeper comprising such inclined surface 10a toward the tip (vertical direction of the taper), so that each oxidizing gas passage 10, the air inlet side opening width w ₄ of the other portion is enlarged than the groove width w _5, it is effectively adapted to take in air.
[0030]
In this example, similarly, the width of each rib 11 is similarly formed so as to gradually decrease at the air outlet side end of each oxidizing gas flow path 10, and the bottom surface of the groove gradually increases toward the tip. The opening width on the air outlet side of each oxidizing gas passage 10 is larger than the groove width of the other portion, and the air is efficiently discharged.
[0031]
By the way, the thickness of the separator 4 needs to be reduced as much as possible from the viewpoint of improving the volume output density. It is difficult to secure the channel cross-sectional area by making the groove deep with the separator 4 having such a small thickness. This is because the fuel gas channel 5 is formed on the surface of the separator 4 where the oxidizing gas channel 10 is formed, and the thickness of the fuel gas channel 5 is required. However, a region corresponding to the air inlet end or the outlet end of each oxidizing gas passage 10 is a fuel gas seal portion, and the fuel gas passage 5 is not formed on the back surface side. . Therefore, if this groove is used to form the inclined surface 10a such that the bottom surface of the groove gradually becomes deeper toward the tip, the flow path of the oxidizing gas flow path 10 can be cut without increasing the overall thickness of the separator 4. It is possible to expand the area. Further, by providing the tapered shape using the fuel gas seal portion as described above, the weight of the separator 4 can be reduced.
[0032]
FIG. 6 shows a case where the cross-sectional area of the oxidizing gas flow path 10 is increased by providing a taper in the vertical direction, and a case where a taper is provided in the vertical direction and the left-right direction of the oxidizing gas flow path 10 to increase the flow cross-sectional area. It shows the relationship between the static pressure Ps of the oxidizing gas and the flow rate Q when it is enlarged. It can be seen that the flow resistance reduction effect is greater when the taper is provided in the vertical and horizontal directions of the oxidant gas flow path 10 than when the taper is provided only in the vertical direction of the oxidant gas flow path 10.
[0033]
In the oxidizing gas flow path 10, besides expanding the flow path cross-sectional area, the flow path resistance may be reduced by, for example, performing R chamfering on each edge portion on the air inlet side. Further, the intersection between the bottom surface and the side wall of the groove forming the oxidizing gas flow path 10 may be formed in an arc shape, and the groove shape of the oxidizing gas flow path 10 may be formed so as to have no corner. It is effective in reducing.
[0034]
Furthermore, as a method of reducing the flow path resistance of the oxidizing gas flow path 10, a method such as performing a surface treatment to reduce the flow path resistance can be adopted as in the case of the fuel gas flow path 5 described above. . Examples of the surface treatment include a surface roughening treatment by mechanical processing such as shot peening and a surface roughening treatment by chemical processing such as etching. Further, as the surface treatment, formation of a projection or groove processing may be performed.
[0035]
The relationship between the groove width and the groove depth of the oxidizing gas passage 10 is determined by the ratio of the supply efficiency of the oxidizing gas, the cooling efficiency by air as the oxidizing gas, and the thickness of the separator 4. It is preferable to set in consideration of restrictions. For example, if the ratio (w: d) of the groove width w to the groove depth d is set to 2: 1.5, these requirements can be satisfied. When the ratio of the groove width w is large, for example, when w: d = 2: 1, the flow rate of the oxidizing gas flowing into the oxidizing gas flow path 10 becomes insufficient, which causes a reduction in power generation efficiency and cooling efficiency. Conversely, when the depth ratio is large, for example, w: d = 2: 2, the thickness of the separator 4 must be increased.
[0036]
The separator having the above-described configuration can be used for fuel cells having various configurations. Hereinafter, a configuration example of a fuel cell using this type of separator will be described.
[0037]
As shown in FIG. 7, the fuel cell 20 includes a housing 30, a control board 40 on which various circuits necessary for operating the fuel cell 20 are formed, and a power generation configured using the separator 4 described above. Unit 50, a cooling fan 61 for cooling the power generation unit 50, two air supply fans 62 and 63 corresponding to the above-described air supply unit for supplying air to the power generation unit 50, and a fuel gas flow path 5 includes a hydrogen purge valve 64 for discharging water remaining in the fuel cell 5, a regulator 65 for controlling the pressure of hydrogen gas, and a manual valve 66 for supplying hydrogen gas to the power generation unit 50. Further, although not shown, if necessary, sensors for detecting the temperature, humidity, pressure, and the like of the air taken in from the outside and the air exhausted from the inside of the fuel cell 20 and the temperature of the power generation unit 50 itself are measured. It is provided with a sensor for detecting.
[0038]
Further, a hydrogen storage cartridge 70 storing hydrogen gas is attached to the fuel cell 20. The fuel cell 20 receives hydrogen gas supplied from the hydrogen storage cartridge 70 and performs power generation. That is, the hydrogen storage cartridge 70 corresponds to a hydrogen supply unit that supplies the hydrogen gas described above.
[0039]
As shown in FIGS. 7 and 8, the housing 30 has a substantially rectangular parallelepiped outer shape, and has a hollow inside so as to cover various members mounted on the fuel cell 20, and has an open bottom surface. Be composed. In addition, one side surface of the housing 30 has an inclined surface facing the one side surface.
[0040]
Further, the housing 30 is formed with three exhaust ports 31, 32, 33 and two intake ports 34, 35.
[0041]
As shown in FIG. 8A, the exhaust ports 31, 32, and 33 are formed adjacent to each other on one side surface of the housing 30. The air blown into the fuel cell 20 for cooling the power generation unit 50 and the air after the power generation reaction by the power generation unit 50 are discharged from these exhaust ports 31, 32, and 33, respectively.
[0042]
Specifically, the exhaust port 31 is formed as a slit-shaped opening on one side surface of the housing 30, and a plurality of openings are arrayed vertically in the one side surface, and the exhaust port 31 is formed on the one side surface. The opening is formed such that the length of the opening in the longitudinal direction is gradually reduced in the vertical direction, and the overall shape is substantially circular. The exhaust port 31 is provided as an air outlet for discharging air from the fuel cell 20 for releasing heat through a radiation fin described later.
[0043]
Similarly to the exhaust port 31, each of the exhaust ports 32 and 33 is formed as a slit-shaped opening on one side surface of the housing 30, and a plurality of openings are arrayed vertically in the one side surface. At the same time, the opening is formed such that the length in the longitudinal direction of the opening in the vertical direction of one side surface is gradually reduced, and the overall shape is substantially circular. Each of the exhaust ports 32 and 33 is provided as an outlet for discharging the air supplied to the power generation unit 50 when the power generation unit 50 generates power.
[0044]
On the other hand, as shown in FIG. 8B, the air inlets 34 and 35 are formed so as to be adjacent to each other on the other side facing the one side on which the outlets 31, 32 and 33 are formed in the housing 30. Is done. From these intake ports 34 and 35, air for cooling the power generation unit 50 and air containing oxygen used for the power generation reaction by the power generation unit 50 are taken into the fuel cell 20. Specifically, the intake port 34 is formed so as to open in a substantially rectangular shape on the side surface of the housing 30, and a plurality of openings are arranged and formed vertically in the side surface. The air intake port 34 is provided as an air intake port through which air for radiating heat via a radiation fin described later is taken into the fuel cell 20. Similarly to the intake port 34, the intake port 35 is opened in a substantially rectangular shape on the other side surface of the housing 30, and a plurality of intake ports 35 are formed in the vertical direction on the one side surface. The intake port 35 is provided as an intake port through which air supplied to the power generation unit 50 is taken in when power is generated by the power generation unit 50.
[0045]
Further, as shown in FIG. 7, FIG. 8 (c) and FIG. 8 (d), a wiring for transmitting and receiving various signals between the fuel cell 20 and the outside is provided on one end surface of the housing 30. Connection holes 36 and 37 for insertion into the fuel cell 20 are formed, and a required connection hole 38 is formed on the other end surface.
[0046]
Various circuits including a control circuit for controlling various members constituting the fuel cell 20 are formed on the control board 40. The control board 40 is provided above the power generation unit 50. Although details of the control circuit formed in the control circuit 40 are not particularly shown, for example, a control circuit for controlling the driving of the cooling fan 61 and the air supply fans 62 and 63, and the opening and closing operation of the hydrogen purge valve 64 are controlled. A voltage conversion circuit such as a direct current to direct current (DC / DC) converter for boosting a voltage output from the power generation unit 50, and various environmental conditions such as temperature and humidity detected by a sensor described later. Thus, a control circuit or the like for giving an instruction regarding driving of various members is mounted. Although the control board 40 is described here as being provided inside the fuel cell 20, the control board 40 may be provided outside the fuel cell 20. Various electronic devices to which the power is supplied may be provided.
[0047]
As shown in FIGS. 7 and 9, the power generation unit 50 has a substantially rectangular parallelepiped outer shape, and a part of a side surface facing the side surface 56 facing the cooling fan 61 and the air supply fans 62 and 63 extends vertically. The shape is a rectangular shape.
[0048]
Specifically, as shown in FIG. 9, the power generation unit 50 is configured such that, for example, a joined body 51 as a power generator is sandwiched between nine separators 4, whereby a unit element that generates power is formed. It has a stack structure in which eight are connected in series.
[0049]
As shown in FIG. 10, the unit element includes the above-described two separators 4 and a joined body 51 sandwiched between the two separators 4. Note that FIG. 2 shows two unit elements connected in series.
[0050]
Radiator fins 52 are provided on the separator 4 so as to protrude out of the plane where the fuel gas flow path 5 and the oxidizing gas flow path 10 are formed. In the separator 4, heat is radiated through the radiating fins 52 by the action of the cooling fan 61, as described later. The separator 4 is provided with a plurality of oxidizing gas channels 10 on the back side. In the separator 4, as described later, the air is supplied to the oxidizing gas passage 10 by the action of the air supply fans 62 and 63, thereby realizing the flow of the air inside the power generation unit 50.
[0051]
The bonded body 51 is formed by a solid polymer electrolyte membrane 53 having ion conductivity when absorbing moisture, and electrodes 54 sandwiching the solid polymer electrolyte membrane 53 from both sides. As the solid polymer electrolyte membrane 53, for example, a sulfonic acid-based solid polymer electrolyte membrane can be used. Further, as the electrode 54, an electrode supporting a catalyst for promoting a power generation reaction can be used.
[0052]
A sealing member 85 that seals the space between the separator 4 and the joined body 51 when the stack structure is formed as the power generation unit 50 is disposed near the periphery of the joined body 51. The sealing member 55 is made of a material that can sufficiently insulate the peripheral edge of the separator 4 from the peripheral edge of the joined body 51. Further, as the sealing member 55, it is preferable to use a material having high thermal conductivity in order to enhance the heat radiation of the power generation unit 50. A material having an electrically insulating property is preferable.
[0053]
Such a unit element can output, for example, a voltage of about 0.6 V with one element, and the power generation unit 50 shown in FIG. 10 has eight unit elements connected in series. , And a total voltage of 4.8 V can be output. Further, the power generation unit 50 can flow a current of about 2 A. Thus, the power output from the power generation unit 50 is theoretically 9.6 W, but is actually about 6.7 W which is about 70% of the ideal output power due to heat generation in the power generation reaction. It is about. However, the power generation unit 50 can further increase the output power by appropriately adjusting the amount of moisture contained in the joined body 51 or realizing a smooth supply of hydrogen gas to the power generation unit 50. . The number of the unit elements forming the power generation unit 50 is not necessarily eight, but may be set to a required number according to the output power required to drive various electronic devices.
[0054]
The power generation unit 50 has a stack structure by connecting a plurality of such unit elements in series. Therefore, as shown in FIG. 9, the outlets of the plurality of oxidizing gas passages 10 formed in the respective separators 4 face one side surface 56 of the power generation unit 50, and the other side surface has the illustrated side. Although not shown, the power generation unit 50 is configured such that the above-described supply ports in the plurality of oxidizing gas channels 10 face the respective discharge ports.
[0055]
As shown in FIG. 7, a cooling fan 61 and air supply fans 62 and 63 are provided in the power generation unit 50 along the side surface 56 so as to be adjacent to each other. The power generation unit 50 is provided with a hydrogen purge valve 64, a regulator 65, and a manual valve 66 adjacent to each other along the end face.
[0056]
The cooling fan 61 is provided along the side surface 56 between the exhaust port 31 formed in the housing 30 and the radiation fin 52 of the power generation unit 50, and cools the power generation unit 50. Specifically, as shown in FIG. 11, the cooling fan 61 blows air taken in from the air inlet 34 formed in the housing 30 to the air outlet 31 and discharges the air outside the fuel cell 50.
[0057]
As described above, in the fuel cell 20, heat can be radiated from the power generation unit 50 through the radiating fins 52 by flowing the air by the cooling fan 61 so as to pass through the radiating fins 52.
[0058]
The position where the cooling fan 61 is provided is not limited to the vicinity of the radiation fins 52, and may be provided at a position where air flows through the entire inside of the fuel cell 20 for the purpose of cooling the power generation unit 50. Good. Further, in the fuel cell 20, air may be blown in the opposite direction by rotating the cooling fan 61 in the reverse direction.
[0059]
The air supply fans 62 and 63 are provided along the side surface 56 between the exhaust ports 32 and 33 formed in the housing 30 and the area of the power generation unit 50 facing the exhaust port of the oxidizing gas flow path 10, respectively. , And supplies air to the power generation unit 50. Specifically, as shown in FIG. 11, the air supply fans 62 and 63 respectively supply the air taken in from the intake port 35 formed in the housing 30 to the exhaust ports 32 and 33 via the power generation unit 50. Fluid is discharged to the outside of the fuel cell 20.
[0060]
As described above, in the fuel cell 20, the air is supplied by the air supply fans 62 and 63 so as to pass through the power generation unit 50, so that the oxidant gas flow path formed in the separator 4 constituting the power generation unit 50. 10 can be supplied with air.
[0061]
In the fuel cell 20, similarly to the cooling fan 61, the air may be caused to flow in the opposite direction by rotating the air supply fans 62 and 63 in reverse. Further, the flow of air formed by each of the air supply fans 62 and 63 can be made independent of the flow of air formed by the cooling fan 61. Therefore, in the fuel cell 20, by independently driving the cooling fan 61 and the air supply fans 62 and 63, the cooling of the power generation unit 50 and the supply and discharge of air to the power generation unit 50 are performed independently. Becomes possible. In particular, in the fuel cell 20, the temperature of the power generation unit 50 and the amount of moisture remaining in the power generation unit 50 are measured, and the air supply fans 62 and 63 and the cooling fan 61 are independently driven according to the measured values. For example, stable power generation can be performed without causing a problem during power generation such as dry-up.
[0062]
The hydrogen purge valve 64 discharges the fuel exhaust gas having a reduced hydrogen concentration or an increased impurity concentration by opening the fuel gas flow path 5 formed in the separator 4 to the atmosphere, and furthermore, stays in the fuel gas flow path 5. Drain water. That is, in the fuel cell 20, when the fuel gas flow path 5 is opened to the atmosphere by opening the hydrogen purge valve 64, as described above, the supply of the hydrogen gas on the supply path side to the water retained in the fuel gas flow path 5 is performed. A pressure difference occurs between the pressure and the pressure on the discharge side that is open to the atmosphere, and the water remaining in the fuel gas flow path 5 is discharged by the pressure difference.
[0063]
As described above, in the fuel cell 20, when the power generation unit 50 has a stack structure, a pressure difference is generated between the side of supplying hydrogen gas and the side of water discharged to the atmosphere by the hydrogen purge valve 64. Even in this case, it is possible to discharge water from the fuel gas passage 5 where the hydrogen gas is difficult to flow due to the influence of the staying water, and it is possible to smoothly flow the hydrogen gas through the fuel gas passage 5.
[0064]
In the fuel cell 20, the hydrogen purge valve 64 may be driven by a driving method using, for example, an electromagnetic force, and the power for driving the hydrogen purge valve 64 may be supplied from the power generation unit 50. You may.
[0065]
The regulator 65 controls the pressure of the hydrogen gas supplied from the hydrogen storage cartridge 70, adjusts the pressure of the hydrogen gas to a predetermined pressure, and supplies the hydrogen gas to the power generation unit 50. For example, when the pressure of the hydrogen gas supplied from the hydrogen storage cartridge 70 is, for example, about 0.8 MPa to 1.0 MPa, the regulator 65 raises the pressure of the hydrogen gas to, for example, about 0.05 MPa to 0.10 MPa. The pressure is reduced to a pressure and supplied to the power generation unit 50.
[0066]
The manual valve 66 is provided for supplying hydrogen gas to the power generation unit 50. When the power generation unit 50 performs power generation, a flow path for supplying hydrogen gas from the hydrogen storage cartridge 70 to the power generation unit 50 is provided. To release.
[0067]
In the fuel cell 20 including such components, a region for disposing the cooling fan 61, the air supply fans 62 and 63, the hydrogen purge valve 64, the regulator 65, and the manual valve 66 is secured around the power generation unit 50. In addition, various members for driving the fuel cell 20 can be housed in the housing 30 in a compact manner, so that the fuel cell 20 can be significantly reduced in size.
[0068]
Therefore, the fuel cell 20 having the above configuration can be used with any electronic device including various types of portable electronic devices such as, for example, a notebook personal computer, a mobile phone, or a personal digital assistant (PDA). It can be used very suitably as a power supply for supplying electric power for driving.
[0069]
Further, in the above-described fuel cell, since the fuel cell separator 4 in which the flow passage cross-sectional areas of the oxidizing gas flow passage 10 on the air inlet side and the outlet side are enlarged is used, the air supply fan 62 , 63 can be reduced, and the overall power generation efficiency of the fuel cell can be improved. Further, since the oxidizing gas is efficiently supplied, the air supply fans 62 and 63 can be downsized, and the volume output density of the fuel cell can be improved. Further, the number of rotations of the air supply fans 62 and 63 can be reduced, and the silent operation of the fuel cell is possible. Furthermore, since the flow rate of the air as the oxidizing gas increases, there is an advantage that the cooling effect is improved.
[0070]
【The invention's effect】
As is clear from the above description, according to the fuel cell separator of the present invention, it is possible to efficiently take in the oxidizing gas. Therefore, in the fuel cell using such a separator, the overall power generation efficiency can be improved, the volume output density can be improved, and furthermore, the silent operation can be performed.
[Brief description of the drawings]
FIG. 1 is an exploded schematic perspective view showing a power generation portion of a fuel cell.
FIG. 2 is a schematic plan view of a fuel gas flow path forming surface of a fuel cell separator.
FIGS. 3A and 3B are enlarged cross-sectional views each showing a part of a fuel cell separator, wherein FIG. 3A shows the vicinity of an inlet, and FIG. 3B shows the vicinity of an outlet.
FIG. 4 is a schematic plan view of an oxidizing gas flow path forming surface of a fuel cell separator.
FIG. 5 is a schematic perspective view of an oxidizing gas flow path forming surface of a fuel cell separator.
FIG. 6 is a characteristic diagram showing the relationship between the static pressure Ps of the oxidizing gas and the flow rate Q when the cross-sectional area of the oxidizing gas flow path is increased by providing a taper in the oxidizing gas flow path.
FIG. 7 is an exploded perspective view showing a structural example of a fuel cell.
8A and 8B are diagrams showing a structure of a casing constituting the fuel cell, wherein FIG. 8A is a side view of one side, FIG. 8B is a side view of the opposite side, FIG. 8C is an end view, d) is an end view showing the other end face.
FIG. 9 is a perspective view showing a schematic configuration of a power generation unit constituting the fuel cell.
FIG. 10 is an exploded perspective view showing a part of a power generation unit constituting the fuel cell.
FIG. 11 is a plan view showing the structure of a fuel cell.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electrolyte membrane 2, 3 Electrode 4 Separator 5 Fuel gas flow path 6 Fuel supply hole 7 Fuel discharge hole 8 Inlet 9 Outlet 10 Oxidant gas flow path 10a Inclined surface 11 Rib 11a Inclined surface 12 Fuel supply passage 13 Exhaust passage

Claims (12)

While having a fuel gas flow path on one side, having an oxidizing gas flow path on the other side,
The fuel cell separator according to claim 1, wherein the oxidizing gas flow path has an enlarged flow path cross-sectional area on the oxidizing gas inlet side and reduced flow path resistance. A plurality of grooves are arranged and formed in parallel with each other across the rib as the oxidant gas flow path,
The rib is formed so that the width thereof is gradually reduced on the inlet side of the oxidizing gas, and the groove width of each groove serving as the oxidizing gas flow path is increased toward the oxidizing gas inlet side. The fuel cell separator according to claim 1, wherein Each groove as the oxidant gas flow path has a bottom surface inclined toward the oxidant gas inlet on the oxidant gas inlet side, and the groove depth of each groove serving as the oxidant gas flow path is on the oxidant gas inlet side. The fuel cell separator according to claim 2, wherein the separator is expanded toward. 2. The fuel cell separator according to claim 1, wherein an edge of the oxidizing gas passage on the oxidizing gas inlet side is rounded. 2. The fuel cell separator according to claim 1, wherein the oxidant gas flow path is subjected to a surface treatment for reducing flow path resistance. The fuel cell separator according to claim 5, wherein the surface treatment is a roughening treatment by mechanical processing. The fuel cell separator according to claim 5, wherein the surface treatment is a surface roughening treatment by chemical processing. 6. The fuel cell separator according to claim 5, wherein a projection is formed or a groove is formed as the surface treatment. 2. The fuel cell separator according to claim 1, wherein the oxidizing gas flow path has a cross-sectional area of the flow path enlarged at the outlet side of the oxidizing gas to reduce flow resistance. A stack comprising an ion conductor having ion conductivity and electrodes facing each other with the ion conductor interposed therebetween, and a separator sandwiching the junction, and a stack in which these junctions and the separator are stacked The separator has a fuel gas flow path on one surface and an oxidizing gas flow path on the other surface, and the oxidizing gas flow path is formed on the inlet side of the oxidizing gas. A fuel cell characterized in that a road cross-sectional area is enlarged and flow path resistance is reduced. The fuel cell according to claim 10, further comprising an oxidizing gas supply device that supplies an oxidizing gas to the oxidizing gas flow path. The fuel cell according to claim 11, wherein the oxidant gas supply device is a fan or a pump.

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