JP4868302B2 - Fuel cell, cell structure and manufacturing method thereof - Google Patents

Description

  The present invention relates to a fuel cell and a method for manufacturing the same, and more particularly to a fuel cell that can be miniaturized and a method for manufacturing the same.

  In recent years, countermeasures against environmental problems and resource problems have become important, and fuel cells have attracted attention as one of the countermeasures. In particular, direct fuel cells use methanol as fuel and can directly generate power without reforming or gasification, so the structure is simple, and it is easy to reduce the size and weight. It is promising as a small-sized consumer power supply for computers. In a direct methanol fuel cell, generally, when an aqueous methanol solution is supplied to the fuel electrode side, carbon dioxide gas is generated by the cell reaction, and waste fuel and carbon dioxide gas are discharged as fuel exhaust. On the other hand, when air is supplied as an oxidant on the air electrode side, water is generated by a battery reaction and is discharged together with air.

  When a direct methanol fuel cell is used in this way, the operating voltage of the direct methanol fuel cell has a low output voltage per cell, so it is necessary to boost the voltage by connecting a plurality of cells in series. For this reason, normally, as shown in FIG. 1, the pressure is increased by laminating via a separator or the like, so an increase in size is inevitable, and a further reduction in size is required.

  A conventional fuel cell is generally formed by sandwiching an electrolyte material between two electrodes through a separator and accommodating it in a battery case or the like. In order to reduce the size of such a fuel cell, FIG. It has been proposed that the electrodes be miniaturized by using a microfabrication technique or the like for producing a semiconductor as shown in FIG.

Japanese Patent Laid-Open No. 2004-111343 JP-A-2002-280016 Japanese Patent Laid-Open No. 2003-264003

  However, for the electrolyte part of fuel cells, the above-mentioned semiconductor microfabrication technology cannot be used as a material normally used as an electrolyte. Conversely, if a ceramic material that can be microfabricated is used as an electrolyte material, the performance is extremely high. Since the shape of the electrolyte portion is almost the same as the conventional one even when the electrode is downsized, the battery as a whole cannot be effectively downsized.

  In addition, in the case of a battery in which an electrode is sandwiched between conventional electrolyte materials, an electrolyte material that is slightly larger than the electrode is usually used in order to prevent short-circuit between electrodes or fuel leakage, but it is larger than the electrode of the electrolyte material. The portion becomes a portion that cannot be used as an operation of the fuel cell (for example, referring to FIG. 2, since the electrode 201 has a structure sandwiching the electrolyte membrane 202, the portion of the electrolyte that is not sandwiched between the electrodes) Does not play a role as an electrolyte part at all), resulting in a problem of wasting expensive electrolyte material.

  The present invention has been made in view of such problems, and by making the structure of the electrolyte portion miniaturizable, it proposes a new cell structure of a fuel cell and uses the electrolyte efficiently. Objective. Another object of the present invention is to provide a low-cost fuel cell by avoiding waste of electrolyte material.

In order to achieve such an object, the cell structure of the present invention includes a plurality of electrolyte portions formed by filling a plurality of holes formed through one non-conductive substrate with an electrolyte material, and the plurality of electrolyte portions. A plurality of electrodes disposed on the exposed surface of the non- conductive substrate surface of each of the electrolyte portions by covering an upper surface and a lower surface of the hole portion with an electrode material, and exposing each of the plurality of electrolyte portions One of the electrodes arranged on the surface is arranged on the opposite side between one of the electrodes and the non-conductive substrate among the electrodes arranged on both sides of the electrolyte part adjacent to the electrolyte part. By connecting to the other electrode, it is possible to generate power by supplying fuel only to either the upper surface or the lower surface of the non-conductive substrate .

The fuel cell of the present invention is a fuel cell comprising an electrode, an electrolyte part, a fuel supply part, and an oxygen supply part, wherein the electrolyte part is formed through one non-conductive substrate. A plurality of electrolyte parts formed by filling the plurality of holes with an electrolyte material, and the electrodes are exposed on the non- conductive substrate surface of each of the plurality of electrolyte parts, and the upper and lower surfaces of the hole parts A plurality of electrodes disposed by coating the electrode material with the fuel material , wherein the fuel supply portion is disposed only on one surface of the non-conductive substrate, and the electrode disposed on each exposed surface of the plurality of electrolyte portions. One of the electrodes arranged on both sides of the electrolyte part adjacent to the electrolyte part is connected to one of the electrodes and another electrode arranged on the opposite side across the non-conductive substrate. The upper or lower surface of the non-conductive substrate Characterized in that it is a possible power by supplying fuel only to Reka.

Furthermore, in the method for manufacturing a cell structure of the present invention, a plurality of holes are formed through one non-conductive substrate, and the formed holes are filled with an electrolyte material to form a plurality of electrolytes. And a step of disposing a plurality of electrodes on the exposed surface of the non- conductive substrate surface of each of the plurality of electrolyte portions by covering an upper surface and a lower surface of the hole portion with an electrode material. One of the electrodes disposed on each exposed surface of the electrolyte part includes one of the electrodes disposed on both sides of the electrolyte part adjacent to the electrolyte part and the non-conductive substrate . It is possible to generate power by supplying fuel only to either the upper surface or the lower surface of the non-conductive substrate by connecting to another electrode disposed on the opposite side across the gap .

  As described above, according to the present invention, a new fuel cell is provided by including an electrolyte part formed by filling a part of a nonconductor with an electrolyte material and an electrode disposed on a side part of the electrolyte part. A cell structure is proposed and the electrolyte can be used efficiently. Moreover, a low-cost fuel cell can be provided by avoiding waste of the electrolyte material.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Fuel cell structure)
FIG. 3 is a cross-sectional view showing the structure of a fuel cell according to an embodiment of the present invention. The electrolyte portion in the conventional fuel cell uses the plate-like electrolyte material as it is as described above, whereas the electrolyte portion of the present invention fills the electrolyte material in the hole formed in the non-conductive substrate. Created in shape. That is, the electrolyte part of the present invention is not formed into a form that is incorporated into the cell structure by cutting the electrolyte material itself as in the prior art, but a portion that fills the electrolyte part in a non-conductive substrate or the like constituting the cell. Yes, and the electrolyte material is filled so that the electrolyte part is formed in that part. Therefore, if the electrolyte part used for the fuel cell has such a structure, it is within the technical scope of the present invention, and the shape of the structure and the method for forming the electrolyte part may be any method. For example, as a method of forming the electrolyte part, a method of forming a hole in the non-conductor part and pouring the electrolyte solution into the hole part is also possible, or a method of forming both the electrolyte material and the non-conductor part. it can. After all, it can be said that a fuel cell having an electrolyte part with a structure in which an electrolyte material is embedded in a non-conductor of any shape and material regardless of the formation method is included in the technical scope of the present invention.

  The fuel cell of the present embodiment shown in FIG. 3 has an electrolyte part having a structure in which a polymer electrolyte 304 is poured into a hole formed in a non-conductive substrate 301 and dried and fixed. Here, the non-conductive substrate forms the basis of the cell structure of the fuel cell according to the present embodiment, and the electrodes 303 and 302 are formed on the electrolyte portion formed in this way to form the cell structure of the fuel cell. . Therefore, any solid non-conductive material such as plastic or glass can be used as long as it achieves such an object, and the shape is limited to a plate-like material as in this embodiment. Absent.

  FIG. 4 is a view showing a non-conductive substrate in which a plurality of holes are formed in producing the fuel cell of the present embodiment. The non-conductive substrate 301 is regularly formed with a fixed cylindrical hole 401, and the hole 401 is formed so as to penetrate the non-conductive substrate 301. By forming the hole in this manner, for example, if the fuel electrode is placed on the upper surface side and the air electrode is placed on the bottom surface side, the cell can be easily created. However, the hole 401 does not need to penetrate the non-conductive substrate, and if the structure for supplying air or fuel is provided on the bottom surface side, it is not necessary to open only the top surface or both surfaces.

  In the present embodiment, the electrolyte material in the hole 401 of the non-conductive substrate 301 shown in FIG. 4 constitutes the electrolyte part 304, and electrodes are embedded in the electrolyte part 304 from both sides. Referring to FIG. 3, since the methanol aqueous solution 306 as fuel is supplied from the upper side, it can be understood that the fuel electrode 303 may be embedded above the non-conductive substrate 301 and the air electrode 302 may be embedded below. In the present embodiment, the three cells have a series structure in which the fuel electrode 303 and the air electrode 302 are electrically connected by the conductor connecting portion 305, but of course, the number of cells is not limited to three. Obviously, the method can be other than that shown in FIG. In this embodiment, the conductor connection portion 305 has a series connection structure as described later, but other methods can be used as long as the object is achieved.

  Actually, many series connection structures have been proposed (see, for example, Patent Document 2 or 3), but it is a person skilled in the art to combine the cell structure of this embodiment with these techniques to achieve further effects. If so, you can understand.

  Fuel and oxygen are supplied to the cell structure having the above structure to generate electric power as a fuel cell. The fuel and oxygen supply method and the structure of the apparatus are well known in the art, and any of such techniques can be applied to the cell structure of this embodiment. In the present embodiment, the fuel 306 is a methanol aqueous solution, and the operation as a fuel cell is basically the same as that of the DMFC (direct methanol fuel cell) of the prior art, and therefore the description thereof is omitted here. Needless to say, any cell having the basic structure of the embodiment can be used as a cell for DMFC as well as other types of fuel cells.

(Fuel cell manufacturing method)
Next, a method for manufacturing a fuel cell, that is, a method for forming the cell structure of the present invention will be described. FIG. 5 is a flowchart showing the cell structure forming method of the present embodiment.

  First, a non-conductive material is prepared by cutting into a plate shape, and a hole is formed by forming a hole (S501). Next, an electrolyte material is embedded in the formed hole (S502) and fixed to form an electrolyte part (S503). In the present embodiment, the electrolyte solution is poured into the pores, heat-treated after drying, and fixed to form the electrolyte portion. When the electrolyte part is formed, an electrode catalyst is embedded on both sides of the electrolyte part (S504), and finally wiring is performed (S505).

  The above is an example of the cell structure manufacturing method of the present invention. However, those skilled in the art will know how to manufacture a fuel cell that is known in this technical field or that will be developed in the future using the cell structure thus obtained. Further, it can be applied to manufacture a fuel cell, but the details are omitted. Further, there are various methods for manufacturing a fuel cell from such a cell structure, but it is clear that a fuel cell can be manufactured by any of the manufacturing methods using the cell structure of the present invention.

Example 1
Next, an example of a fuel cell using the cell structure of this embodiment will be described with reference to FIG. In this embodiment, a 1 mm thick substrate of polysulfone resin is used as the non-conductor 301, but the material is not limited to this. However, in this example, since certain heat resistance, acid resistance, and alcohol resistance are necessary, the material satisfying these was used.

  Since the hole of this embodiment is penetrated in a circle having a diameter of 0.5 mm, the shape of the hole 401 is a cylinder having a height of 1 mm and a diameter of 0.5 mm. 0.2 μl of 20 wt% Naflon solution is injected into the hole 401 and dried at room temperature for 30 minutes. Thereafter, the polymer electrolyte is fixed to the pores by performing heat treatment for 10 minutes in an electric furnace set to 135 ° C. (usually 120 ° C. to 140 ° C. is desirable). Thereby, an electrolyte part is formed.

  Next, the cell structure of the fuel cell of this example is created by applying an electrode catalyst on both sides of the polymer electrolyte. As the electrode catalyst, a platinum catalyst or a platinum ruthenium alloy catalyst is mixed well with an electrolyte solution, and a paste-like suspension is prepared and applied. That is, this catalyst suspension is applied to both sides of the polymer electrolyte, dried at room temperature for about 30 minutes, and heat-treated at 135 ° C. (usually 120 ° C. to 140 ° C.) for 1 minute using a hot press. Thus, an electrode is formed. Finally, wiring for current leads is created by a method of depositing gold on the substrate.

FIG. 6 is a graph showing the output characteristics of a fuel cell using one cell of this example. Using a methanol solution (5 wt%) as the fuel, the methanol solution was directly supplied to the fuel electrode, and air was supplied by natural aspiration, and the power output was confirmed by the DMFC method. Thus, it can be understood that the single cell performance of the fuel cell according to the present example is 1.6 mW / cm ² at a normal temperature.

FIG. 8 shows the output characteristics of a fuel cell similarly formed by connecting three cells in series. The fuel and air conditions are the same as in the case of one cell described with reference to FIG. Referring to FIG. 8, it can be understood that in the case of the cell of the present embodiment, the cell has a cross section of 0.5 mm in diameter, so that in the case of using three fuel cells, the output density is approximately 3.8 mW / cm ² .

  As described above, the electrolyte can be used efficiently, and a low-cost fuel cell can be provided by avoiding waste of the electrolyte material.

(Example 2)
In this embodiment, a non-conductive substrate made of glass is used instead of the non-conductive substrate of polysulfone resin used in the above-described embodiment. Since the non-conductive substrate of this example has sufficient heat resistance, acid resistance, and alcohol resistance, it is optimal for the implementation of the present invention. Since other points are the same as those in the first embodiment, description thereof is omitted.

(Example 3)
FIG. 7 is a diagram showing a series connection structure of the present embodiment. As can be understood from the prior art or the above-described first embodiment, generally, a single cell cannot obtain the required voltage of the fuel cell. Therefore, the cells are usually connected in series by any method to obtain the required voltage. Need to get. The necessary voltage is about 3 to 5 V for use in an electronic device, but some devices require a higher voltage.

  In this embodiment, electrodes are wired as shown in FIG. 7 in order to connect the cells in series. FIG. 7 is a top view of the substrate of this embodiment, but not only the conductive cell coupling members 701 and 706 on the upper surface side but also the conductive cell coupling members 704 and 705 on the lower surface side. The electrodes of each cell are electrically connected to each other. That is, there is a part of the cell junction 705 below the cell portion 702, and the conductor connection portion 305 is coupled to one end 703 of the cell coupling member 706 so as to penetrate the non-conductive substrate 301 on the upper surface side. Connected to the cell junction 706. Thereafter, the same connection is performed, the cells are connected in series, and the cell junction 701 to the cell junction 704 are directly connected. In this embodiment, 13 cells are connected in series.

  FIG. 8 shows the output characteristics of the fuel cell of this example in which the cells of Example 1 described above are connected in series with the structure of this example. By connecting in series in this way, a more practical voltage can be obtained. As described above, the electrodes can be connected in series by a microfabrication technique to obtain a practical voltage and to reduce the size of the entire battery.

It is a figure which shows an example of the stack structure of the conventional fuel cell. It is a figure which shows the example which refined | miniaturized the electrode using the microfabrication technique for producing the conventional semiconductor. It is sectional drawing which shows the structure of the fuel cell concerning one Embodiment of this invention. It is a figure which shows the non-conductive board | substrate which opened the some hole part in producing the fuel cell of this embodiment. It is a flowchart which shows the cell structure formation method of this embodiment. It is a figure which shows the output characteristic of the fuel cell using one cell of a present Example. It is a figure which shows the serial connection structure of a present Example. It is a figure which shows the output characteristic of the fuel cell using three cells of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Stack structure 102 Separator 103 Fuel electrode 104 Solid polymer film 105 Air electrode 201 Electrode 202 Electrolyte membrane 301 Non-conductive substrate 302, 303 Electrode 304 Polymer electrolyte 305 Conductor connection part 306 Fuel 401 Hole part 701, 704, 705, 706 Cell Joint part 702 Cell part 703 One end of the cell joint part

Claims (6)

A plurality of electrolyte portions formed by filling a plurality of holes formed through one non-conductive substrate with an electrolyte material;
A plurality of electrodes disposed on the exposed surface of the non-conductive substrate surface of each of the plurality of electrolyte portions by covering an upper surface and a lower surface of the hole portion with an electrode material, and each of the plurality of electrolyte portions One of the electrodes disposed on the exposed surface of the first electrode is an opposite side of the electrode disposed on both sides of the electrolyte portion adjacent to the electrolyte portion, with one of the electrodes sandwiching the non-conductive substrate. A cell structure characterized in that power can be generated by supplying fuel only to either the upper surface or the lower surface of the non-conductive substrate by connecting to another electrode disposed on the substrate.   The cell structure according to claim 1, wherein the non-conductive substrate is a polysulfonic acid resin substrate. The cell structure according to claim 1, wherein the non-conductive substrate is a glass substrate. The electrolyte material is a polymer electrolyte,
4. The cell structure according to claim 1, wherein the electrode is a platinum or platinum ruthenium catalyst electrode. A fuel cell comprising an electrode, an electrolyte part, a fuel supply part, and an oxygen supply part,
The electrolyte part is a plurality of electrolyte parts formed by filling a plurality of holes formed through one non-conductive substrate with an electrolyte material,
The electrodes are a plurality of electrodes arranged by coating an electrode material on an upper surface and a lower surface of the hole portion on the exposed surface of the non-conductive substrate surface of each of the plurality of electrolyte portions,
The fuel supply unit is disposed only on one side of the non-conductive substrate,
One of the electrodes disposed on the exposed surface of each of the plurality of electrolyte portions may include one of the electrodes disposed on both sides of the electrolyte portion adjacent to the electrolyte portion and the non-conductor. A fuel cell characterized in that power generation is possible by supplying fuel only to the upper surface or the lower surface of the non-conductive substrate by connecting to another electrode disposed on the opposite side across the substrate. . Forming a plurality of holes through one non-conductive substrate;
Filling the formed pores with an electrolyte material to form a plurality of electrolyte portions;
Arranging a plurality of electrodes on the exposed surface of each of the plurality of electrolyte portions on the surface of the non-conductive substrate by covering an upper surface and a lower surface of the hole with an electrode material, and the plurality of electrolyte portions One of the electrodes disposed on each exposed surface of each of the electrodes is one of the electrodes disposed on both sides of the electrolyte part adjacent to the electrolyte part and sandwiches the non-conductive substrate. A method of manufacturing a cell structure, wherein power generation is possible by supplying fuel only to either the upper surface or the lower surface of the non-conductive substrate by connecting to another electrode disposed on the opposite side.

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