JP2008047453A - Fuel cell and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell capable of proving sufficient power output, sufficiently reduced in size and weight, downsized, and capable of being provided at low cost; and its manufacturing method. <P>SOLUTION: In this fuel cell having a flat stack structure, an electrolyte membrane 2 is composed by impregnating an electrolyte into a strip-like base body formed of a fiber body. A unit cell is composed by arranging the respective electrolyte membranes 2 along the longitudinal direction of the strip-like base body, and by forming fuel electrodes 15 and air electrodes 16 on one-side surface side and the other-side surface side of the respective electrolyte membranes 2, respectively. The fuel electrodes 15 of a specific one of the unit cells are electrically connected the air electrodes 16 of the unit cell adjacent to it through conductors such as electroless gold plating 8 or porous electrode material extending by piercing the strip-like base body. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell and a manufacturing method thereof.

  In recent years, direct methanol fuel cells (DMFC) have attracted attention. This is because energy more than several times that of a lithium secondary battery may be extracted, and if methanol is supplied, it can be used continuously without being charged. Therefore, application to mobile devices such as notebook computers and mobile phones has been attempted.

  The basic structure of a fuel cell has a membrane electrode assembly in which a fuel electrode and an air electrode are joined on both sides of an electrolyte membrane through which hydrogen ions pass. In practice, a battery is constructed by connecting a plurality of unit batteries having such a structure. In such a case, a planar stack structure has been proposed to make the whole compact (see, for example, Patent Document 1 and Patent Document 2).

In the planar stack structure of Patent Document 1, a plurality of through holes are formed in an electrically insulating substrate, and unit cells made of the membrane electrode assembly are disposed in the through holes, and each unit cell is electrically connected. Are connected in series or in parallel. In addition, the planar stack structure of Patent Document 2 has a structure in which a membrane electrode assembly is continuously formed on a web-like base material constituting the air electrode side diffusion layer as a connecting material.
JP-A-62-200666 JP-A-2005-294123

  However, it is difficult to say that the fuel cell disclosed in Patent Document 1 is sufficiently small, light, and compact, and therefore it is particularly suitable for application to mobile devices such as notebook computers and mobile phones. There is no state. In addition, the production requires a lot of work and the cost is not satisfactory. Furthermore, since the fuel cell of Patent Document 2 has a structure in which all the air electrodes are used in common and the unit cells are connected in parallel, it is difficult to say that a sufficient output can be obtained.

  The present invention has been made in order to solve the above-described conventional drawbacks. The object of the present invention is to provide a sufficient output, as well as being sufficiently small, light and compact, and can be provided at a low cost. The object is to provide a fuel cell and a method of manufacturing the same.

  Accordingly, in the fuel cell of claim 1, in the fuel cell having a planar stack structure, the electrolyte membrane 2 is configured by impregnating the strip-shaped substrate 1 made of a fibrous body with an electrolyte, and each electrolyte membrane 2 is formed on the strip-shaped substrate 1. A unit cell is formed by arranging the fuel electrode 15 on one surface side of each electrolyte membrane 2 and the air electrode 16 on the other surface side while arranging them along the longitudinal direction. The fuel electrode 15 of the battery is characterized in that it is electrically connected to the air electrode 16 of the unit cell adjacent thereto by a conductor extending through the strip substrate 1.

  In the fuel cell according to claim 2, an insulating agent impregnated layer 4 for partitioning each electrolyte membrane 2 is formed in the longitudinal direction of each electrolyte membrane 2, and the insulating agent impregnated layer between adjacent unit cells is formed. 4 is formed with a conductor penetrating portion 3 that allows the conductor to pass therethrough.

  The fuel cell according to claim 3, wherein the conductor is an electroless gold plating 8, and when performing electroless gold plating as a fuel electrode side electrode material and an air electrode side electrode material, the gold plating 8 is on the fuel electrode side of a specific unit cell. The catalyst 5 is applied to the air electrode side catalyst 6 of the unit cell adjacent to the catalyst 5 and is further continuous through the conductor penetrating portion 3.

  The fuel cell according to claim 4, wherein the conductor is a porous electrode material 9 applied by printing, and when the porous electrode material 9 is printed as a fuel electrode side electrode material and an air electrode side electrode material, the conductor penetrates. It is characterized by intruding into the part 3.

  The fuel cell according to claim 5 is characterized in that the belt-like substrate 1 is made of a nonwoven fabric.

  The method of manufacturing a fuel cell according to claim 6 includes the step of partitioning the electrolyte region 2a to be the electrolyte membrane 2 by impregnating the strip substrate 1 with the insulating agent 4 at a predetermined interval in the longitudinal direction, and the electrolyte region. A step of impregnating 2a with an electrolyte to form the electrolyte membrane 2, a step of forming a fuel cell 15 and an air electrode 16 on the front and back surfaces of the electrolyte membrane to form a unit cell, and a fuel electrode 15 of a specific unit cell And a step of electrically connecting the air electrodes 16 of the unit cells adjacent to each other by a conductor extending through the band-shaped substrate 1.

In the method of manufacturing a fuel cell according to claim 7, in the step of partitioning the electrolyte region 2a, a conductor through portion 3 that allows passage of the conductor is provided between the insulating impregnated layers 4 between adjacent unit cells. It is characterized by being formed.

  According to the fuel cell of claim 1, the electrolyte membrane 2 can be formed by impregnating the belt-like substrate 1 with the electrolyte, and each fuel electrode 15 and each of the fuel electrode 15 and each of the belt-like substrate 1 from the same surface side. Since the forming operation with the air electrode 16 can be performed, a fuel cell that can be manufactured with high efficiency can be provided. Further, since no extra space is required for connecting the unit batteries, the size and weight can be reduced and the size can be reduced. Moreover, because of the series connection structure, a sufficient output can be obtained. Furthermore, in use, the belt-like substrate 1 can be folded and used, so that it can be configured compactly.

  According to the fuel cell of the second aspect, the dimensional accuracy of the electrolyte membrane 2 can be improved, and the unit cells can be reliably connected by the conductor.

  According to the fuel cells of claims 3 and 4, the unit cells can be connected at a low cost, and a reliable connection state can be obtained. The fuel cell according to claim 5 is suitable for the implementation.

  According to the fuel cell manufacturing method of the sixth aspect, since the electrolyte membrane 2 is formed by impregnating the strip substrate 1 with the electrolyte, the fuel cell can be manufactured with high efficiency. Moreover, since the electrolyte region 2a is partitioned in advance with an insulating agent, the dimensional accuracy of the electrolyte membrane 2 can be improved.

  According to the fuel cell of the seventh aspect, the unit cells can be reliably connected by the conductor.

  Next, specific embodiments of the fuel cell and the manufacturing method thereof according to the present invention will be described in detail with reference to the drawings. First, a first embodiment of a manufacturing method will be described with reference to FIGS. 1 and 2. In FIG. 1 (a), reference numeral 1 denotes a belt-like substrate. The substrate 1 is continuous in the left-right direction in the figure and is made of a fibrous body such as a polyester nonwoven fabric. In the following manufacturing method, although not shown, positioning guide holes are formed at predetermined intervals on both sides of the belt-like substrate 1, and the belt-like substrate 1 is fed intermittently like a progressive press. However, it is preferable to perform each process of FIG. 1 (a)-(d) and FIG. 2 (a) (b).

  A plurality of electrolyte membranes 2 are formed on the substrate 1 in the form of islands at predetermined intervals as shown in FIG. 2C. Prior to that, as shown in FIG. Further, an insulating agent is impregnated by a printing method except for a predetermined width between the electrolyte region 2a for forming the electrolyte membrane 2 and the adjacent electrolyte regions 2a, 2a. That is, the insulating agent impregnated layer 4 is formed on the front, rear, right and left of the electrolyte membrane 2 to partition the electrolyte region 2a, and the conductor penetration part 3 is formed between the insulating agent impregnated layers 4 and 4 of the adjacent electrolyte regions 2a and 2a. I will keep it. This conductor penetration part 3 is a state with the nonwoven fabric which is not impregnated with the insulating agent. As the insulating agent, acid polyester, PTFE (Teflon: registered trademark), polyimide, polypropylene, polyethylene, polycarbonate, or the like can be used. Next, as shown in FIG. 6C, an electrolyte made of an ion exchange resin (for example, Nafion (registered trademark of DuPont)) is dissolved in a solvent by a printing method or the like in a square (square) electrolyte region 2a. The electrolyte membrane 2 is formed by impregnating the electrolyte solution.

  After that, the fuel electrode (anode) 15 and the air electrode (cathode) 16 are formed on both the front and back surfaces of the electrolyte membranes 2... Respectively, but the fuel electrode side catalyst 5 on the surface side (upper side) is (Pt-Ru / C). ), The back side (lower side) air electrode side catalyst 6 is (Pt-C), and these catalysts 5 and 6 are printed as shown in FIG. The fuel electrode 15 is composed of the fuel electrode side catalyst 5 and a fuel electrode side electrode material disposed on the surface thereof, and the air electrode 16 is disposed on the air electrode side catalyst 6 and the surface thereof. Although it consists of an air electrode side electrode material, in this embodiment, each electrode material is comprised by the electroless gold plating 8. FIG. The electroless gold plating method will be described below.

  As shown in FIG. 2A, the catalyst 7 for electroless plating is printed. At the time of printing, the catalyst 7 is printed on the fuel electrode 15 over a region including the fuel electrode side catalyst 5 and the conductor penetrating portion 3 adjacent to the right side in the drawing. Further, in the air electrode 16, the catalyst 7 is printed over a region including the air electrode side catalyst 6 and the conductor penetration part 3 adjacent to the left side in the drawing. As a result, in each conductor penetration part 3, the catalyst 7 printed on the fuel electrode side catalyst 5 of the specific unit cell A and the catalyst printed on the air electrode side catalyst 6 of the unit cell B adjacent to this catalyst 7 are printed. 7 overlaps vertically.

  When the electroless gold plating 8 is applied to the printed state of the catalyst 7 in this way, a planar stack structure of the unit cell in the state shown in FIG. 2B is obtained. That is, the electroless gold plating 8 continues from the fuel electrode side catalyst 5 of the specific unit cell A through the conductor penetrating part 3 to the air electrode side catalyst 6 of the unit cell B adjacent thereto. It is in an electrically connected state.

  In the fuel cell having the planar stack structure, the electrolyte membrane 2 is formed by impregnating the strip-shaped nonwoven fabric strip-shaped substrate 1 with the electrolyte, the fuel electrode 5 is formed on the upper side, and the air electrode 6 is formed on the lower side. Thus, a unit cell is formed. Further, the unit cells are arranged in parallel along the longitudinal direction of the belt-like substrate 1, and the unit cells are connected in series with each other.

  FIG. 3 shows a fuel cell according to a second embodiment of the present invention and a method for manufacturing the same. In this embodiment, the steps in FIGS. 1A to 1D are the same as those in the first embodiment, and the description thereof is omitted. In this embodiment, the fuel electrode side electrode material of the fuel electrode 15 and the air electrode side catalyst 6 of the air electrode 16 are configured not by the electroless gold plating 8 but by printing a porous electrode. This is different from the above-described embodiment. First, the porous electrode material 9 is printed on the fuel electrode side catalyst 5 on the fuel electrode 15 side. At this time, as shown in FIG. 3A, printing is performed on a region including the fuel electrode side catalyst 5 and the conductor penetration portion 3 adjacent to the right side in the drawing. If it does so, the porous electrode material 9 will be printed also including the inside of the conductor penetration part 3. FIG. Next, as shown in FIG. 3B, printing is performed on an area including the air electrode side catalyst 6 on the air electrode 16 side and the conductor through-hole 3 adjacent to the left side in the drawing. . Then, the planar stack structure of the unit cell in the state shown in FIG. That is, the porous electrode material 9 continues from the fuel electrode side catalyst 5 of the specific unit cell A through the conductor penetration part 3 to the air electrode side catalyst 6 of the unit cell B adjacent thereto, Are electrically connected.

  According to the fuel cell of each of the above embodiments, the electrolyte membrane 2 can be formed by impregnating the strip substrate 1 with an electrolyte, and each fuel electrode 15 and the strip electrode 1 can be formed from the same surface side. Since the forming operation with each air electrode 16 can be performed, a fuel cell that can be manufactured with high efficiency can be provided. In addition, since the conductor penetrating portion 3 is provided in the belt-like substrate 1 and the conductor (electroless gold plating 8 and porous electrode material 9) is passed through the conductor penetrating portion 3 for electrical connection, an extra space is required. Is not required. Accordingly, it is possible to reduce the size, weight and size. Moreover, because of the series connection structure, a sufficient output can be obtained. Furthermore, in use, the belt-like substrate 1 can be folded and used, so that it can be configured compactly. In addition, since the electrolyte region 2a is partitioned by the insulating agent impregnated layer 4 and the electrolyte membrane 2 is formed in this region 2a, the dimensional accuracy of the electrolyte membrane 2 can be improved.

  Moreover, according to each manufacturing method of the fuel cell, since the electrolyte membrane 2 is formed by impregnating the belt-like substrate 1 with the electrolyte, the fuel cell can be manufactured with high efficiency. Moreover, since the electrolyte region 2a is partitioned in advance with an insulating agent, the dimensional accuracy of the electrolyte membrane 2 can be improved.

  Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, in the above, a non-woven fabric is used as the belt-like substrate 1, but this may be a woven fabric or paper.

FIG. 6 is a simplified process diagram for explaining the first half of the first embodiment in the method for producing a fuel cell of the present invention. It is a simplified process diagram for explaining the latter half of the process of the first embodiment in the fuel cell manufacturing method of the present invention. It is a simplified process diagram for demonstrating the latter half process of 2nd Embodiment in the manufacturing method of the fuel cell of this invention.

Explanation of symbols

  1 .. Strip substrate 2 .. Electrolyte membrane 2a .. Electrolyte region 3 .. Conductor penetration part 4 .. Insulating agent impregnated layer 5 .. Fuel electrode catalyst 6. Electroless gold plating, 9 ... porous electrode material, 15 ... fuel electrode, 16 ... air electrode

Claims (7)

  In the fuel cell having a planar stack structure, the electrolyte membrane (2) is constituted by impregnating an electrolyte in a strip-shaped substrate (1) made of a fibrous body, and each electrolyte membrane (2) is arranged in the longitudinal direction of the strip-shaped substrate (1). A unit cell is formed by arranging the fuel electrode (15) on one surface side of the electrolyte membrane (2) and the air electrode (16) on the other surface side. The fuel electrode (15) of a specific unit cell is electrically connected to the air electrode (16) of the unit cell adjacent thereto by a conductor extending through the strip substrate (1). A fuel cell characterized by comprising:   An insulating agent impregnated layer (4) partitioning each electrolytic membrane (2) is formed before and after the longitudinal direction of each electrolytic membrane (2), and an insulating agent impregnated layer (4 between adjacent unit cells) is formed. The fuel cell according to claim 1, wherein a conductor penetrating portion (3) that allows the conductor to pass therethrough is formed.   The conductor is electroless gold plating (8). When electroless gold plating is performed as a fuel electrode side electrode material and an air electrode side electrode material, the gold plating (8) is a fuel electrode side catalyst (5) of a specific unit cell. And is applied to the air electrode side catalyst (6) of the unit cell adjacent to each other and further continuous through the conductor penetration part (3). 2. Fuel cell.   The conductor is a porous electrode material (9) applied by printing, and when the porous electrode material (9) is printed as a fuel electrode side electrode material and an air electrode side electrode material, the conductor penetration portion (3) The fuel cell according to claim 2, wherein the fuel cell penetrates into the inside.   The fuel cell according to any one of claims 1 to 4, wherein the belt-like substrate (1) is made of a nonwoven fabric.   A step of partitioning the electrolyte region (2a) to be the electrolyte membrane (2) by impregnating the strip-shaped substrate (1) with the insulating agent (4) at a predetermined interval in the longitudinal direction; and the electrolyte region (2a) A step of forming an electrolyte membrane (2) by impregnating the electrolyte membrane, a step of forming a fuel cell (15) and an air electrode (16) on the front and back surfaces of the electrolyte membrane to form a unit cell, and a specific unit A step of electrically connecting the fuel electrode (15) of the battery and the air electrode (16) of the unit cell adjacent thereto by a conductor extending through the belt-like substrate (1). A method for manufacturing a fuel cell.   In the step of partitioning the electrolyte region (2a), a conductor penetration portion (3) that allows passage of the conductor is formed between the insulating agent impregnated layers (4) between adjacent unit cells. A method for producing a fuel cell according to claim 6.