JP2006066092A - Separator and fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator with reduced thickness and improved draining property of carbon dioxide and water generated by power generation reaction, and also provide a fuel cell stack equipped with the separator with reduced thickness. <P>SOLUTION: The separator can improve the draining property of carbon dioxide and water generated, by gradually deepening a flow passage. The thickness of the separator can be reduced by combining a downstream area with an upstream area. The fuel cell stack loading the separator can prevent lowering of efficiency of power generation reaction, and the thickness of the fuel cell stack can be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a separator mounted on a fuel cell, and also relates to a fuel cell stack on which the separator is mounted.

  A fuel cell is a power generating element that generates power by electrochemically reacting a fuel such as hydrogen or methanol with an oxidant gas such as oxygen. A fuel cell is attracting attention as a power generation element that does not pollute the environment because the product generated by power generation is water. For example, attempts have been made to use it as a drive power source for driving an automobile. Yes.

  Fuel cells are classified into various types depending on the difference in electrolytes and the like, and representatively, fuel cells using a solid polymer electrolyte as an electrolyte are known. Solid polymer electrolyte fuel cells are promising as drive power sources for electronic devices because they can be reduced in cost, are easy to reduce in size, thickness and weight, and have high output density in terms of battery performance. is there. This solid polymer electrolyte fuel cell has also been developed in which hydrogen and hydrogen are generated by reforming methanol and natural gas in addition to hydrogen to produce fuel. In recent years, direct methanol fuel cells have also been developed that generate electricity by supplying methanol directly to the fuel cell as fuel.

  A direct methanol fuel cell includes an electrode electrolyte assembly in which an electrolyte membrane and a pair of electrodes are integrated on a base plate, a flat separator having a fuel channel on one side and an oxidant gas channel on the other side, Are alternately stacked, an aqueous methanol solution is supplied to the fuel flow path, and air is supplied to the oxidant gas flow path to cause a power generation reaction on the electrolyte membrane.

  FIG. 1 is a plan view showing the oxidant gas flow path side of a conventional separator. As shown in FIG. 1, the separator 9 conventionally used is provided with an oxidant gas flow path 90 in a flat plate member. An oxidant gas flow path inlet 91 for supplying air, which is an oxidant gas, is provided at the end of the oxidant gas flow path 90, and the oxidant gas from which the air flowing through the flow path is discharged at the other end. A channel outlet 92 is provided.

  Further, a meandering fuel flow path is provided on the opposite surface of the oxidant gas flow path 90 in the same manner as the oxidant gas flow path 90. A fuel flow path inlet 93 for supplying a methanol aqueous solution as fuel to the fuel flow path is provided at the end of the fuel flow path, and a fuel flow path outlet 94 for discharging the methanol aqueous solution is provided at the other end. . The oxidant gas channel inlet 91, the oxidant gas channel outlet 92, the fuel channel inlet 93, and the fuel channel outlet 94 penetrate the separator 9. And it seals so that methanol aqueous solution and air may not leak outside.

  FIG. 2 is a cross-sectional view showing the shape of the AA ′ cross section of the separator shown in FIG. As shown in FIG. 2, the oxidant gas flow path and the fuel flow path of the conventional separator 9 have a constant flow path depth and a constant flow path width as shown in FIG. However, the separator 9 has a problem in that water and carbon dioxide remain in the flow path due to generation of carbon dioxide and water due to the power generation reaction, leading to a decrease in efficiency of the power generation reaction.

  On the other hand, a separator that increases the depth of the flow path from the upstream to the downstream of the flow path has been reported (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 10-302813

  However, in the separator of Patent Document 1, since the flow path depth becomes deeper as it goes downstream of the flow path, the thickness of the separator is determined at the deepest flow path depth, and the thickness of the separator increases. Has a point.

  Therefore, in view of such a conventional situation, the present invention aims to provide a separator that improves discharge of carbon dioxide and water generated by a power generation reaction and is thinned, and further, a separator that is thinned It aims at providing the fuel cell stack provided with.

  The separator of the present invention is a separator that is alternately stacked with a joined body that sandwiches an electrolyte between a pair of electrodes, and gradually increases the depth from one upstream side to the other side of a flat plate member in order to flow fuel. A fuel channel formed to be deep and a surface opposite to the surface having the fuel channel to flow through the oxidant gas channel so that the depth gradually increases from upstream to downstream. And an upstream side of the fuel channel is formed in a region on the opposite side of the region corresponding to the region forming the downstream side of the oxidant gas channel. The downstream side of the passage is formed in a region on the opposite surface corresponding to the region forming the upstream side of the oxidant gas flow path.

  According to the separator of the present invention, the discharge depth of the generated carbon dioxide and water is improved by gradually increasing the depth of both the fuel flow channel and the oxidant gas flow channel from upstream to downstream. be able to. Further, the upstream side of the fuel flow path is formed in the area on the opposite side corresponding to the area forming the downstream side of the oxidant gas flow path, and the opposite side corresponding to the area forming the upstream side of the oxidant gas flow path. By forming the downstream side of the fuel flow path in the region of the side surface, the flow path is formed avoiding the deepest part of both flow paths, and the separator can be made thin.

  The fuel cell stack of the present invention includes a fuel flow path formed so as to gradually increase in depth from upstream to downstream on one surface of a flat plate member for flowing fuel, and an oxidant gas flow path An oxidant gas channel formed so as to gradually increase in depth from upstream to downstream on the surface opposite to the surface having the fuel channel. The upstream side is formed in an area on the opposite side corresponding to the area forming the downstream side of the oxidant gas flow path, and the downstream side of the fuel flow path forms the upstream side of the oxidant gas flow path The joined body that sandwiches the electrolyte between the pair of electrodes is sandwiched between the separators formed in the region on the opposite surface corresponding to the region to be performed.

  According to the fuel cell stack of the present invention, by mounting the above-described separator, it is possible to prevent a decrease in efficiency of the power generation reaction due to carbon dioxide and water generated in the power generation reaction. Further, the formed fuel cell stack can be thinned by the thinned separator.

  The separator of the present invention can improve the discharge of generated carbon dioxide and water by gradually increasing the depth of both the fuel channel and the oxidant gas channel from upstream to downstream. it can. Moreover, a separator can be made thin by forming a flow path avoiding the deepest place of both flow paths.

  By mounting the above-described separator, the fuel cell stack of the present invention can prevent the efficiency of the power generation reaction due to carbon dioxide and water generated by the power generation reaction. Further, the formed fuel cell stack can be thinned by the thinned separator.

  Hereinafter, the separator and the fuel cell stack of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following description, and can be appropriately changed without departing from the gist of the present invention.

  FIG. 3 is a plan view showing an example of the separator of the present invention. As shown in FIG. 3A, the separator 1 of the present invention has a fuel flow path 10 that meanders on one surface of a flat plate member in order to flow a methanol aqueous solution as a fuel. A fuel supply port 100 for supplying a methanol aqueous solution to the fuel flow channel 10 and a fuel discharge port 101 for discharging the methanol aqueous solution flowing through the fuel flow channel 10 are separators at the end of the fuel flow channel 10. 1 is provided so as to penetrate 1. The fuel channel 10 is formed so as to gradually increase the channel depth from the fuel supply port 100 upstream of the channel toward the fuel discharge port 101 downstream of the channel.

  As shown in FIG. 3B, the separator 1 of the present invention meanders on the surface opposite to the surface having the fuel flow path 10 in order to flow the air as the oxidant gas, like the fuel flow path 10 described above. An oxidant gas flow path 11 is provided. An oxidant gas supply port 110 for supplying air to the oxidant gas flow path 11 and an oxidant gas for discharging the air flowing through the oxidant gas flow path 11 are provided at the end of the oxidant gas flow path 11. A discharge port 111 is provided so as to penetrate the separator 1. The oxidant gas channel 11 is formed so as to gradually increase the channel depth from the oxidant gas channel supply port 110 upstream of the channel toward the fuel gas discharge port 111 downstream of the channel. ing.

  In the separator 1 of the present invention, the upstream side of the fuel flow channel 10 is formed in a region on the opposite surface corresponding to the region forming the downstream side of the oxidant gas flow channel 11. Is formed in the region on the opposite surface corresponding to the region forming the upstream side of the oxidant gas flow path 11.

  The separator 1 of the present invention sandwiches a joined body in which an electrolyte is sandwiched between a pair of electrodes, and transmits electric power generated in the joined body by an aqueous methanol solution and air to an external circuit. Therefore, as a material of the plate-like member forming the separator 1 of the present invention, the electrical conductivity is good, and it is not corroded by fuel such as oxidant gas such as air or methanol aqueous solution. It is possible to use a material having a high airtightness that prevents mixing with the material. For example, carbon or a metal material may be used, and the surface thereof may be subjected to a plating treatment for rust prevention.

  The fuel flow path 10 is formed on one surface of the separator 1 that is a substantially flat plate member. The fuel flow path 10 is a flow path for flowing a methanol aqueous solution as a fuel. By supplying the methanol aqueous solution to the fuel flow path 10, the methanol aqueous solution can be supplied to the joined body. A fuel supply port 100 for supplying an aqueous methanol solution to the fuel flow path 10 is provided upstream of the fuel flow path 10. Further, a fuel discharge port 101 for discharging the methanol aqueous solution flowing through the fuel flow path 10 to the outside of the separator 1 is provided downstream of the fuel flow path 11.

  The fuel flow path 10 is formed so as to gradually become deeper from the upstream on the fuel supply port 100 side toward the downstream on the fuel discharge port 101 side. In the fuel flow path 10, the flow of the methanol aqueous solution is deteriorated by carbon dioxide generated by the power generation reaction, and the efficiency of the power generation reaction is reduced. Therefore, by gradually deepening the flow path, it is possible to easily move the carbon dioxide in the flow path toward the fuel discharge port 101 using the inclination of the flow path. Therefore, the carbon dioxide emission can be improved.

  A fuel supply port 100 connected to one end of the fuel flow path 10 is formed so as to penetrate the separator 1. Therefore, when alternately laminating the separator 1 and the joined body in which the electrolyte is sandwiched between the pair of electrodes, the fuel supply port 100 of each separator 1 can be communicated. For example, by supplying a methanol aqueous solution to the fuel supply port 100 of the lowermost separator 1 of the laminated body in which the separator 1 and the joined body are stacked, each of the separators 1 is connected via the fuel supply port 100 that is in communication. An aqueous methanol solution can be supplied to the fuel flow path 10. The shape and size of the fuel supply port 100 can be appropriately changed depending on the shape and size of the separator 1 and the shape and number of the fuel flow paths 10 formed in the separator 1.

  The fuel discharge port 101 is connected to the other end of the fuel flow path 10 to which the fuel supply port 100 is connected, and is formed so as to penetrate the separator 1. Therefore, when alternately laminating the separator 1 and the joined body in which the electrolyte is sandwiched between the pair of electrodes, the fuel discharge port 101 of each separator 1 can be communicated. Therefore, the methanol aqueous solution can be discharged from the fuel discharge port 101. The shape, size, and the like of the fuel discharge port 101 can be changed as appropriate depending on the shape and size of the separator 1 and the shape and number of the fuel flow paths 10 formed in the separator 1.

  The oxidant gas channel 11 is formed on the surface of the separator 1 opposite to the surface on which the fuel channel 10 is formed. The oxidant gas passage 11 is a passage through which air, which is an oxidant gas, flows. By supplying air to the oxidant gas passage 11, air can be supplied to the joined body. An oxidant gas supply port 110 that supplies air to the oxidant gas flow path 11 is provided upstream of the oxidant gas flow path 11. Further, an oxidant gas discharge port 111 for discharging the air flowing through the oxidant gas flow path 11 to the outside of the separator 1 is provided downstream of the oxidant gas flow path 11.

  The oxidant gas flow path 11 is formed so as to gradually deepen from the upstream side of the oxidant gas supply port 110 side toward the downstream side of the oxidant gas discharge port 111 side. In the oxidant gas flow path 11, the flow of air supplied to the flow path is deteriorated by water generated by the power generation reaction, and the efficiency of the power generation reaction is reduced. Therefore, by gradually deepening the flow path, the water in the flow path can be easily moved in the direction of the oxidant gas discharge port 111 using the inclination of the flow path. Therefore, the water discharge performance can be improved.

  An oxidant gas supply port 110 connected to one end of the oxidant gas flow path 11 is formed so as to penetrate the separator 1. Therefore, when the separator 1 and the joined body in which the electrolyte is sandwiched between the pair of electrodes are alternately stacked, the oxidant gas supply port 110 of each separator 1 can be communicated. For example, by supplying air to the oxidant gas supply port 110 of the separator 1 on the lowermost surface of the laminated body in which the separator 1 and the joined body are stacked, Air can be supplied to the oxidant gas flow path 11 of the separator 1.

  The oxidant gas discharge port 111 is connected to the other end of the oxidant gas flow path 11 to which the oxidant gas supply port 110 is connected, and is formed so as to penetrate the separator 1. Therefore, when the separator 1 and the joined body in which the electrolyte is sandwiched between the pair of electrodes are alternately stacked, the oxidant gas discharge port 111 of each separator 1 can be communicated. Therefore, air can be discharged from the oxidant gas discharge port 111. The shape, size, and the like of the oxidant gas discharge port 111 can be changed as appropriate depending on the shape and size of the separator 1 and the shape, number, and the like of the oxidant gas flow path 11 formed in the separator 1.

  FIG. 4 is a diagram showing the relationship between the fuel flow path and the oxidant gas flow path of the separator of the present invention. In the separator 1 of the present invention, the upstream side of the fuel flow path 10 is formed in a region on the opposite surface of the separator 1 corresponding to the region forming the downstream side of the oxidant gas flow path 11. The downstream side is formed in a region on the opposite surface of the separator 1 corresponding to a region forming the upstream side of the oxidizing gas channel 11. The fuel channel 10 and the oxidant gas channel 11 are substantially the same and have a uniform channel width. Therefore, as shown in FIG. 4, both flow paths are formed so that the shadows of the fuel flow path 10 and the oxidant gas flow path 11 substantially overlap. Thereby, even if the separator 1 of the present invention is laminated through the joined body, the oxidant gas flow path 11 of another separator 1 can be provided near the fuel flow path 10.

  FIG. 5 is a cross-sectional view showing a BB ′ cross-sectional shape of the separator of the present invention shown in FIG. 3. As shown in FIG. 5, the separator 1 of the present invention is formed so that a portion having a relatively shallow channel depth on the upstream side of the channel and a portion having a relatively deep channel depth on the downstream side of the channel can be combined. ing. Therefore, the separator can be made thinner compared to the case where only one of the channels is gradually deepened or when the deep portions of both channels are combined.

  FIG. 6 is a schematic diagram relating to the flow path depth between the conventional separator and the separator of the present invention. That is, it is a figure which shows the supply port of both the flow paths when both flow paths are made linear. In a separator having a flow path with no change in the conventional flow path depth, the flow path depth does not change, so the thickness of the separator depends on the depth of the flow path. Therefore, when attempting to increase the flow path depth, the separator becomes thicker by the depth of the flow path.

  On the other hand, as shown in FIG. 6, the separator 1 of the present invention combines a flow path depth of one flow path and a shallow flow path of the other flow path so that each flow path is complemented. The increase in the thickness of the separator 1 accompanying the increase in the path depth can be suppressed. That is, the separator 1 of the present invention can increase the depth of the flow path and can relatively reduce the thickness of the separator.

  As described above, the separator 1 of the present invention includes the fuel flow path 10 and the oxidant gas flow path 11 that gradually increase the flow path depth, and the oxidant gas flow is provided upstream of the fuel flow path 10. It is formed in the area of the opposite surface corresponding to the downstream area of the passage 11, and the downstream side of the fuel flow path 11 is formed in the area of the opposite surface corresponding to the upstream area of the oxidant gas flow path 11. Has been.

  The aqueous menotal solution that is the fuel is supplied from the fuel supply port 100. Since the fuel supply port 100 communicates with each separator 1, the aqueous methanol solution supplied to the fuel supply port 100 flows into the fuel flow path 10 of each connected separator 1.

  The aqueous methanol solution that has flowed into the fuel flow path 10 causes the above-described power generation reaction while moving downstream of the fuel flow path 10. The methanol aqueous solution is discharged out of the separator 1 through the fuel discharge port 101 together with the mixed carbon dioxide.

  On the other hand, oxygen, which is an oxidant gas, is supplied from the oxidant gas supply port 110. Since the oxidant gas supply port 110 communicates with each separator 1 in the same manner as the fuel supply port 100, the air supplied to the oxidant gas supply port 110 is connected to the oxidant gas supply port 110 of each separator 1. Into the oxidant gas flow path 11.

  The air that has flowed into the oxidant gas flow path 11 causes the above power generation reaction while moving to the downstream side of the oxidant gas flow path 11. And air is discharged | emitted out of the separator 1 through the oxidizing gas discharge port 111 with the mixed water.

  When the methanol aqueous solution is supplied to the fuel flow path 10 and the air is supplied to the oxidant gas flow path 11, a power generation reaction occurs in the joined body. Due to the power generation reaction, a part of methanol in the aqueous methanol solution and a part of oxygen in the air are used to generate carbon dioxide and water. Since carbon dioxide is generated on the fuel flow path 10 side, it is mixed in the fuel flow path 10, and water is generated on the oxidant gas flow path 11 side, so that it is mixed in the oxidant gas flow path 11.

  Carbon dioxide generated on the fuel flow path 10 side is mixed into the fuel flow path 10 through which the aqueous methanol solution flows. At this time, the separator 1 of the present invention can improve the discharge of carbon dioxide mixed in the fuel flow path 10 by gradually deepening the fuel flow path 10 from upstream to downstream.

  Carbon dioxide, which is a gas, generally moves higher than an aqueous methanol solution, and the aqueous methanol solution moves lower than carbon dioxide. Therefore, by forming the fuel flow path 10 above the joined body, the flow path depth gradually deepened from the upstream to the downstream is utilized to facilitate the movement of carbon dioxide downstream. Can do. Thereby, the discharge property of the carbon dioxide mixed in the fuel flow path 10 can be improved.

  Further, water generated on the oxidant gas flow path 11 side is mixed into the oxidant gas flow path 11 through which air flows. At this time, the oxidant gas flow path 11 is formed so as to gradually deepen from the upstream toward the downstream. Therefore, it is possible to improve the discharge performance of the water mixed in the oxidant gas channel 11.

  Water, which is a liquid, generally moves below air, and air moves above water. Since the oxidizing gas channel 11 gradually increases the depth of the channel from upstream to downstream, the bottom surface of the oxidizing gas channel 11 is inclined from upstream to downstream. Therefore, the water mixed in the oxidant gas channel 11 is likely to move downstream. Thereby, the discharge property of the water mixed in the oxidant gas channel 11 can be improved.

  As described above, the separator 1 of the present invention is not limited to one having a flow path having a constant flow path width. For example, it may be formed so that the width of the flow path is gradually widened, or may be formed so that the width of the flow path is gradually narrowed.

  FIG. 7 is a plan view of the separator of the present invention in which the widths of the fuel flow path and the oxidant gas flow path are gradually increased. The dotted line in the figure is a diagram showing the flow path on the back side. As shown in FIG. 7, the separator 3 has a fuel flow path 30 on one side and an oxidant gas flow path 31 on the other side. The fuel flow path 30 is formed so as to gradually increase the flow path depth from the fuel supply port 300 toward the fuel discharge port 301. On the other hand, the oxidant gas flow path 31 is formed so as to gradually increase the flow path depth from an oxidant gas supply port (not shown) toward the oxidant gas discharge port 311.

  As shown in FIG. 7, the shadows of the fuel flow path 30 and the oxidant gas flow path 31 are substantially overlapped, and the separator 3 is laminated via a joined body in which an electrolyte is sandwiched between a pair of electrodes. However, as described above, the fuel gas channel 30 and the oxidant gas channel 31 of the separator 3 can be provided.

  FIG. 8 is a cross-sectional view showing a CC ′ cross-sectional shape of the separator of the present invention shown in FIG. As shown in FIG. 8, the separator 3 of the present invention is formed so that a portion having a relatively shallow channel depth on the upstream side of the channel and a portion having a relatively deep channel depth on the downstream side of the channel can be combined. ing. Therefore, the separator can be made thinner compared to the case where only one of the channels is gradually deepened or when the deep portions of both channels are combined.

  In this way, by increasing the width of the flow path, the water and carbon dioxide discharge properties can be further improved. At this time, by forming the fuel flow path and the oxidant gas flow path as opposed to each other as much as possible via the joined body, methanol and oxygen in the flow path can be made as close as possible, and the efficiency of the power generation reaction can be improved. Can be improved.

  FIG. 9 is a plan view of the separator of the present invention in which the widths of the fuel flow path and the oxidant gas flow path are gradually narrowed. The dotted line in the figure is a diagram showing the flow path on the back side. As shown in FIG. 9, the separator 4 has a fuel channel 40 on one surface and an oxidant gas channel 41 on the other surface. The fuel flow path 40 is formed so as to gradually increase the flow path depth from the fuel supply port 400 toward the fuel discharge port 401. On the other hand, the oxidizing gas channel 41 is formed so as to gradually increase the channel depth from an oxidizing gas supply port (not shown) toward the oxidizing gas discharge port 411.

  As shown in FIG. 9, the shadows of the fuel flow path 40 and the oxidant gas flow path 41 are substantially overlapped, and the separator 4 is laminated via a joined body in which an electrolyte is sandwiched between a pair of electrodes. However, as described above, the fuel gas channel 40 and the oxidant gas channel 41 of the separator 3 can be provided.

  10 is a cross-sectional view showing a DD ′ cross-sectional shape of the separator of the present invention shown in FIG. 9. As shown in FIG. 10, the separator 4 of the present invention is formed so that a portion having a relatively shallow channel depth on the upstream side of the channel and a portion having a relatively deep channel depth on the downstream side of the channel can be combined. ing. Therefore, the separator can be made thinner compared to the case where only one of the channels is gradually deepened or when the deep portions of both channels are combined.

  Thus, by gradually increasing the flow path depth and gradually reducing the flow path width, the change in the cross-sectional area of the flow path can be prevented from becoming large, and the phenomenon of flow velocity can be prevented. . At this time, by forming the fuel flow path and the oxidant gas flow path as opposed to each other as much as possible via the joined body, methanol and oxygen in the flow path can be made as close as possible, and the efficiency of the power generation reaction can be improved. Can be improved.

  Further, for example, the flow path width of the fuel flow path may be gradually increased from upstream to downstream, and the flow path width of the oxidant gas flow path may be gradually decreased from upstream to downstream. Good and vice versa. It can be appropriately changed according to the inflow amount of the methanol aqueous solution or air, the efficiency of the power generation reaction in the joined body, and the like.

  Next, the fuel cell stack of the present invention will be described. In the fuel cell stack 5 of the present invention, as shown in FIG. 11, a joined body 2 in which an electrolyte 20 is sandwiched between electrodes 21 and 22 and a separator 1 described above that sandwiches the joined body 2 are alternately arranged on a base plate 50. The flat end plate 51 is provided on the top and is press-fitted with a fastening bolt (not shown).

  The joined body 2 includes a substantially rectangular membrane-shaped electrolyte 20 that allows protons to permeate, an electrode 21 and an electrode 22 that have a catalyst in a power generation reaction, and the electrolyte 20 is sandwiched between the electrodes 21 and 22 and bonded together. The electrolyte 20 that allows protons to permeate is formed of a material that has both permeability, oxidation resistance, and heat resistance. An example of the material is a solid polymer such as a perfluorosulfonic acid polymer. The electrode 21 and the electrode 22 are configured using a metal material, a carbon material, a conductive non-woven cloth, or the like. For example, when a carbon material is used, a catalyst such as platinum is supported on the porous surface of the carbon material. good. Further, a diffusion layer having both gas permeability and electrical conductivity made of carbon paper or the like may be disposed on the contact surface between the electrode 21 and the electrode 22 of the joined body 2 and the separator 1. The size and shape of the electrolyte 20, the electrode 21, and the electrode 22 are appropriately changed depending on the required power generation capacity, the size and shape of the separator 1 described later, and the like.

  The base plate 50 is provided with the fuel supply port, the fuel discharge port, the oxidant gas supply port, and the oxidant gas discharge port of the separator 1 described above, and flows through the methanol gas solution and the oxidant gas flow channel that flow through the fuel flow channel. Air can be supplied to and discharged from the separator 1.

  The flat end plate 51 can press-fasten the laminated separator 1 and the joined body 2 with fastening bolts or the like. By being fastened and fastened, the separator 1, the joined body 2, and the separator 1 are brought into close contact with each other with the sealant of the separator 1, and leakage of air and methanol can be prevented.

The fuel cell stack 5 supplies a methanol aqueous solution to the fuel flow path 10 via the fuel supply port and supplies air to the oxidant gas flow path 11 via the oxidant gas supply port, thereby generating a power generation cell. The following reaction can be carried out at 20. In the aqueous solution of methanol, a reaction of CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ occurs at the electrode 21 of the assembly 2 by water and methanol in the aqueous methanol solution. Proton (H ⁺ ) generated by this reaction passes through the electrolyte membrane 20 of the joined body 2 and moves to the electrode 22 of the joined body 2. The generated electrons (e ⁻ ) move from the electrode 21 to the electrode 22 through the external circuit. The protons and electrons that have moved cause a reaction of 3 / 2O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O with oxygen in the supplied air at the electrode 22. Therefore, the fuel cell stack 5 of the present invention can perform a power generation reaction by supplying a methanol aqueous solution and air.

  As described above, a power generation reaction can be caused by supplying an aqueous methanol solution and air. However, due to the power generation reaction, carbon dioxide is generated in the fuel flow path and water is generated in the oxidant gas flow path. . This carbon dioxide and water interfere with the power generation reaction. The fuel cell stack 5 of the present invention can improve the discharge of carbon dioxide and water by using the separator 1 described above. That is, efficient power generation can be performed.

  The separator 1 and the fuel cell stack 5 according to the present invention have been described above. However, the fuel used in the present invention is not limited to methanol, and the fuel used in a normal fuel cell is used. You can also. For example, ethanol or dimethyl ether can also be used.

It is a top view which shows the oxidizing agent gas flow path side of the conventional separator. It is AA 'sectional drawing of the conventional separator. It is a top view which shows an example of the separator of this invention. (A) is a top view which shows the fuel flow path side, (b) is a top view which shows the oxidant gas flow path side. It is a top view which shows the relationship between the fuel flow path and oxidant gas flow path of the separator of this invention. It is BB 'sectional drawing of the separator of this invention shown by FIG. It is a schematic diagram regarding the flow path depth of the separator of this invention. It is a top view which shows the relationship between the fuel flow path and the oxidizing gas flow path of the separator which gradually widens the flow path width of the present invention. It is CC 'sectional drawing of the separator which widens the flow-path width | variety of this invention shown by FIG. It is a top view which shows the relationship between the fuel flow path and oxidant gas flow path of the separator which narrows a flow path width of this invention gradually. FIG. 10 is a cross-sectional view of the separator DD ′ of the present invention shown in FIG. It is a perspective view which shows an example of the fuel cell stack of this invention.

Explanation of symbols

1, 3, 4, 9 Separator 10, 30, 40 Fuel flow path 100, 300, 400 Fuel supply port 101, 301, 401 Fuel discharge port 11, 31, 41, 90 Oxidant gas flow path 110, 310, 410 Oxidation Oxidant gas supply port 111, 311, 411 Oxidant gas discharge port 2 Assembly 20 Electrolyte 21, 22 Electrode 5 Fuel cell 50 Base plate 51 End plate 91 Oxidant gas channel inlet 92 Oxidant gas channel outlet 93 Fuel channel inlet 94 Fuel channel outlet

Claims (7)

A separator alternately laminated with a joined body sandwiching an electrolyte between a pair of electrodes,
A fuel flow path formed to gradually increase the depth from upstream to downstream on one surface of the flat plate member for flowing fuel;
An oxidant gas channel formed so as to gradually increase the depth from upstream to downstream on the surface opposite to the surface having the fuel channel in order to flow the oxidant gas channel;
The upstream side of the fuel flow path is formed in a region of the opposite surface corresponding to the region forming the downstream side of the oxidant gas flow path,
The separator is characterized in that the downstream side of the fuel flow path is formed in an area on the opposite side corresponding to the area forming the upstream side of the oxidant gas flow path.   The separator according to claim 1, wherein the fuel passage has a wider passage width from upstream to downstream.   The separator according to claim 1, wherein the oxidant gas channel has a channel width that increases from upstream to downstream.   The separator according to claim 1, wherein the fuel passage has a narrower passage width from upstream to downstream.   The separator according to claim 1, wherein the oxidant gas flow path has a narrower flow path width from upstream to downstream.   2. The separator according to claim 1, wherein the fuel flow path and the oxidant gas flow path meander. A fuel flow path formed so as to gradually increase in depth from upstream to downstream on one surface of the flat plate member for flowing the fuel, and the fuel flow path for flowing the oxidant gas flow path And an oxidant gas channel formed so as to gradually increase in depth from the upstream side toward the downstream side on the surface opposite to the surface having the oxidant gas. Formed on the opposite surface region corresponding to the region forming the downstream side of the flow path, the downstream side of the fuel flow channel being the opposite side of the region forming the upstream side of the oxidant gas flow channel By the separator formed in the area of the surface,
A fuel cell stack, wherein a joined body that sandwiches an electrolyte is sandwiched between a pair of electrodes.