JP2003263995A - Fuel battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery which can be assembled more easily, and has an improved power generating performance. <P>SOLUTION: In this fuel battery, a cell 3 is constituted so that a plurality of electrodes 1 are arranged on a single plane through a separator 2 in a mutually insulated state, and a pair of separators 2 are connected via an ion- exchange membrane, and a plurality of cells 3 are laminated so that the electrodes 1 are connected in series. In the separators 2, bolt fastening holes 4 for inserting bolts for fastening the plurality of the cells 3 are formed, and the peripheries of the bolt fastening holes 4 of the separators 2 are formed of an insulating member. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, and more particularly to a fuel cell having an improved separator that insulates and holds a plurality of electrodes in the same plane.

[0002]

2. Description of the Related Art In a fuel cell, since a generated electromotive voltage per cell is small, cells are stacked in series to generate a required voltage. Therefore, when trying to obtain a high voltage, the length of the stack (cells stacked) in the stacking direction becomes long, and miniaturization is an issue.

As a solution to the above-mentioned problems, in Japanese Patent Laid-Open No. 8-273696, a plurality of cell parts are provided on a separator such that anodes and cathodes are alternately arranged.
By connecting at the end of the stack, aiming for higher voltage,
A technique of reducing the number of stacked cells is disclosed.

FIG. 3 shows such a technique and the structure of the fuel cell itself.
It will be described with reference to FIGS. FIG. 3 is a schematic diagram showing the configuration of a fuel cell in the conventional example, and FIG. 4 is an explanatory diagram showing the direction of current flow in the fuel cell in the conventional example.

A fuel cell is constructed by stacking a plurality of cells 103 capable of generating electric power using a reaction gas. In particular,
First, as shown in FIG.
A plurality of cells are held on the same plane by being insulated from each other by two, and the cells on this plate are bonded together in pairs through the ion exchange membrane 101a to form the cell 103. That is, a cell portion is formed for each electrode 101 on the same plane. Then, a fuel cell is formed by stacking a plurality of the cells 103. More specifically, a pair of separators 1 integrated with the electrode 101 is provided.
Between 02, the ion exchange membrane 101a and the diffusion layers 101b provided above and below the ion exchange membrane 101a are interposed. The diffusion layer 101b is arranged corresponding to the arrangement of the electrodes 101.

At this time, the separator 102 is partially formed of an electrically conductive and partially insulating fiber composite member, and is press-molded to form a gas flow passage (not shown) used for power generation. ) Is formed. As an example, a non-conductive material containing no carbon particles and a conductive material containing carbon particles are press-molded by adding a binder.

In the example of FIG. 3, one cell 103
In this case, two electrodes 101 are arranged and two cell portions are formed, but the cells 103 are laminated so that the electrodes 101 (cell portions) on the other cells 103 are connected in series with each other. . At this time, one of the cells 103 at one end in the stacking direction is provided with a current collector plate 110 serving as an electrode, and one at the other end is provided with approximately two electrodes 1.
Only one electrode 101 having a size corresponding to 01 (cell portion) is provided. As a result, the two rows of electrodes 101 (cell portions) connected in series by stacking are connected in series. That is, as shown in FIG. 4, a current flows in a U-shape, and a higher voltage can be achieved.

Further, the bind plate 1 having a predetermined thickness is formed at one end and the other end of the cell 103 in the stacking direction.
05 is equipped. A pair of screw holes 104 are formed in the bind plate 105 so that screws (not shown) can be inserted therethrough. Along with this, holes (not shown) corresponding to the screw holes 104 formed in the bind plate 105 are also formed in the separator 102 of each cell 103. Then, these stacked cells 103 are joined by bolts to be integrated.

[0009]

However, in the fuel cell in the above-mentioned conventional example, when the bolts that connect a plurality of cells are inserted, it is necessary to prevent the bolts from coming into contact with cells having a potential difference and short-circuiting. However, there has been a problem in that the coating must be performed with an insulating tube or the like, and that such processing requires labor and cost. This is also because the separator is not entirely made of an insulating material. That is, since the separator is formed by mixing the conductive material and the non-conductive material, a short circuit may occur unless the bolt is coated.

Further, when the bolts are coated with the insulating tubes as described above, the bolts must be fastened by the bind plates located at both ends of the stack, so that a large number of cell portions (electrodes) are arranged on a plane. However, when it is attempted to increase the area of each cell part in order to further increase the voltage, it is difficult to uniformly apply the surface pressure to the entire separator. That is, since the adjacent cells are not fastened to each other, it is difficult to surely adhere them to each other, and it becomes difficult to obtain a uniform surface pressure as the separator area increases, which causes a problem that the power generation performance decreases. Occurs. In such a case, if the binding plate is formed thick in order to increase the fastening force between the binding plates and obtain a large surface pressure, and the threaded portion of the screw hole formed here is taken long, There is also a problem that the weight of the bind plate increases.

Further, since the conductive material and the non-conductive material are mixed in the separator in the conventional example, it is difficult to position the parts using these materials. And
If the fluidity of these materials is high, the conductive materials may come close to each other during pressing, and it is assumed that insulation between cells is insufficient. Considering that the voltage difference between the cells can be several hundreds of volts, there is a problem that resistance loss due to deterioration of insulation performance causes a large decrease in efficiency.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel cell capable of improving the disadvantages of the above-mentioned conventional example, and particularly, facilitating the assembling and improving the power generation performance.

[0013]

Therefore, in the present invention, a plurality of electrodes are arranged on the same plane so as to be insulated from each other via a separator, and a pair of separators are coupled via an ion exchange membrane. And a plurality of cells are stacked so that the electrodes are connected in series. Then, the separator is formed with a bolt fastening hole through which a bolt for fastening a plurality of cells is inserted, and the periphery of the bolt fastening hole of the separator is formed of an insulating member. 1). At this time, if the separator is formed entirely of an insulating member, the design becomes easy, which is desirable (claim 2).

With such a structure, by inserting the bolt into the separator insulated from the electrode (cell portion), it is not necessary to provide an insulating tube or the like on the bolt to coat it. It is possible to reduce time and labor and cost. In addition, since the bolt fastening holes can be formed in all parts of the separator, for example, in the central part of the separator, the cells to be stacked can be fastened to each other in the central part as well, so that the surface pressure can be efficiently applied. Therefore, the power generation performance can be improved. If all of the separators are made of an insulating material, the manufacturing process can be simplified.

Further, it is desirable that the material of the separator is resin and the cell is constructed by connecting the electrode and the separator by injection-molding the separator (claim 3). Thus, the electrodes in the cell, that is, the position of the cell portion that serves as one power generation portion can be accurately arranged, so that the cells can be surely insulated during stacking.

Further, it is more preferable that the resin is a material having flexibility (claim 4). As a result, an appropriate sealing effect can be exerted, and dimensional errors such as flatness and thickness of the cell can be absorbed during stacking, so rattling due to dimensional error can be suppressed, and the entire cell can be suppressed. A uniform surface pressure can be secured.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic diagram showing a configuration in an embodiment of the present invention. FIG. 2 is an explanatory diagram showing details of the cell.

As shown in FIG. 1, in the fuel cell of the present invention, a plurality of electrodes 1 are arranged on the same plane so as to be insulated from each other via a separator 2, and a pair of separators 2 are provided.
The cell 3 is formed by connecting the two via an ion exchange membrane. Since the basic structure of the cell 3 is the same as the conventional one, the description is omitted. A fuel cell is formed by stacking a plurality of the cells 3 as shown in FIG. At this time, the cell parts in which the electrodes 1 of the cells 3 are arranged are positioned so as to be connected in series, and the cells 3 are stacked. Here, in FIG. 1, only one cell 1 is provided, but this is only shown as such for the sake of explanation, and actually, a plurality of cells 1 are provided as shown in FIG.

A plurality of bolt fastening holes 4 for inserting bolts (not shown) are formed in the separator 2 which constitutes the cell 3. Since the bolt fastening holes 4 are formed only in the separator 2, they are formed around the electrode 1. Therefore, for example, as shown in FIG. 1, when two electrodes 1 (cell portions) are arranged in the cell 3, the bolt fastening holes 4 are also provided between these electrodes 1 (the central portion of the cell 3). Is formed. When four electrodes 1 are formed on one cell 3, bolt fastening holes 4 may be formed between the cross-shaped cell portions.

The bolt fastening holes 4 are formed in all the stacked cells 3 so that they are located at substantially the same position. The periphery of the bolt fastening hole 4 is formed of an insulating member. That is, the inner wall surface of the bolt fastening hole 4 of the separator 2 is insulated from the electrode 1. Therefore, even if a bolt is inserted into the hole 4, it is possible to prevent the stacked electrodes 1 from being short-circuited with each other, and it is not necessary to provide an insulating tube or the like on the bolt for coating. As a result, it is possible to reduce labor and cost during such processing.

Then, the entire separator 2 may be formed of an insulating member. As a result, it is not necessary to manufacture a part of the separator 2 by changing the material, so that the manufacturing process can be simplified.

Here, the bolt fastening hole 4 may be a simple cylindrical hole which is not threaded, but the inner wall surface thereof may be threaded. In this way, the cells 3 adjacent to each other are clamped to each other and are surely brought into close contact with each other. At this time, the bind plates 5 are provided on both ends of the cell 3 to be stacked so as to sandwich the cell 3 from the stacking direction.
However, as a matter of course, the binding plate 5 is also formed with the bolt fastening hole 4 so that the cell 3 is securely fastened. However, all the bolt fastening holes 4 are not threaded, and for example, the cells 3 in which the threaded bolt fastening holes 4 are formed and the threaded bolt fastening holes 4 are formed. The damaged cells 3 may be alternately laminated and fastened with bolts. Even in this case, an appropriate fastening force is exerted between the cells 3, so that the surface pressure generated in the cells can be made uniform and the surface pressure can be improved.

Next, the cell 3 will be described in detail with reference to FIG. 2 in particular with respect to only one of the pair of separators 2. Here, FIG. 2A is a diagram illustrating a method of configuring one separator 2, and FIG. 2B is a cross-sectional view of one separator 2 similarly.

The electrode 1 in the cell 3 according to the present invention has a bonding projection 6 uniformly formed around the electrode 1. That is,
Since the electrode 1 has a predetermined thickness, a bonding projection 6 that projects to the periphery is formed at the center in the thickness direction.
The protrusion 6 is further formed with protrusions 7 protruding in the anode and cathode directions of the cell 3 to have a special shape. At this time, the convex portion 7 is formed into the protrusion 6 for joining.
It may be scattered on the top. For example, the convex portions 7 may have a semicircular shape and may be formed on the joining protrusions 6 at predetermined intervals.

Here, the electrode 1 is molded from a resin impregnated with carbon, or a metal having corrosion resistance. Also, copper, aluminum agent, etc. with metal plating excellent in corrosion resistance on the front and back, or clad, or metal with corrosion resistance such as coating the surface with a coating excellent in corrosion resistance and conductivity. It may be molded with the above material.

Then, the electrode 1 is placed at a predetermined position of a separator molding die, and a resin is injected into the separator molding die to mold the separator 2 as shown in FIG. 2 (a). That is, the separator 2 is formed around the electrode 1 by injection molding. Then, the outer peripheries of the two electrodes 1 are completely filled with the separator 2, so that the two electrodes 1 are fixedly arranged on the same plane. In this way, the plate-shaped separator 2 can be manufactured. At this time, the material used as the separator 2 is
For example, it is a rubber and a synthetic resin that have insulating properties and are flexible, such as ethylene propylene rubber (EPDM). However, the material is not limited to this, and may partially have an insulating property as described later, or may not necessarily have flexibility.

By injection molding in this way, FIG.
As shown in (b), the resin comes into close contact with the specially shaped joining projection 6. Therefore, the separator 2 and the electrode 1
Are reliably joined, and the positioning accuracy of the electrode 1 is improved. Moreover, the plurality of electrodes 1 in one cell 3 can be reliably insulated. Further, when the convex portion 7 is formed on the bonding projection 6, the resin intervenes between the convex portions 7 and between the convex portion 7 and the electrode 1 main body portion, so that the separator 2
On the other hand, the position of the electrode 1 can be reliably fixed, and the positioning accuracy of the electrode 1 can be further improved.

Next, the procedure for producing a fuel cell using the cells 3 formed as described above will be described.
First, as shown in FIG. 1 or FIG. 3, the two electrodes 1 arranged in the cell 3 are arranged in series so as to overlap each other in series.
That is, a plurality of cells 3 are stacked so that the cell portions form two rows of layers. At this time, since the separator 2 is injection-molded as described above, the position of the electrode 1 fixed to the separator 2 is accurately positioned, and a deviation (error) from the electrode 1 (cell portion) adjacent in series is generated. Is also suppressed. Therefore, the conductive part (power generation part) where the electrode 1 is located
The position of the insulating part, which is the part of the separator 2, is prevented from being displaced, and it is possible to ensure the insulation.

Thereafter, bind plates 5 are provided at both ends of the stacked cells 3 in the stacking direction, and bolts are inserted into the bolt fastening holes 4 and tightened. At this time, cell 3
Since the bolt fastening hole 4 formed above is formed only in the separator 2 portion which is the insulating resin, the bolt can be used without being insulated with the insulating tube,
Even in such a case, insulation can be surely achieved. Therefore, as compared with the case where the insulating tube is used, the number of parts is reduced, so that the number of manufacturing steps can be reduced and the cost of parts can be reduced.

Further, since the short circuit by the bolt is also suppressed, by inserting the bolt into the central portion of the separator 2, that is, between the plurality of electrodes 1 in the same cell 3, and fastening the same, the entire cell 3 can be obtained. It is possible to apply surface pressure evenly to the.

Further, as described above, by inserting and fastening the bolts at various places such as the central portion of the separator 2, it is possible to maintain an appropriate fastening force even if the diameter of the bolt is reduced, and the cell 3 itself. It is possible to reduce the diameter of the bolt fastening hole 4 and increase the area of the electrode 1, that is, the cell portion without increasing the area of the above, and to further improve the power generation capacity. Therefore, it is possible to suppress the generation of a strong fastening force by using the thick bind plate, and it is possible to maintain an appropriate surface pressure even if the thin bind plate 5 is used, so that the weight of the fuel cell itself can be reduced. Can be planned.

After tightening the bolts, the separator 2 has flexibility, so that the relative error of the positions of the electrodes 1 is absorbed by the separator 2. Therefore, in order to make the surface pressure uniform, there is no need to make dimensional errors such as flatness and thickness of the cell with an error of the order of μm, and even if the area of the separator, which was difficult to make, is large, it is easy In addition to being manufactured, a uniform surface pressure can be secured in the cell unit.

Further, since the separator 2 has flexibility, it has a high affinity with the gasket and a high sealing performance. And even if you don't use gaskets,
It is also possible to directly perform the sealing by using the separator 2 which is an insulating member. As a result, in the conventional example, since the separator has conductivity and was insulated only by the very thin ion exchange membrane of 20 to 50 μm, it was necessary to consider measures such as inserting an insulating sheet. Thus, the gasket can be omitted, and the number of parts can be reduced.

Here, in the above embodiment, the case where the entire separator 2 is formed of an insulating member is mainly illustrated, but the present invention is not necessarily limited to this. An insulating member may be formed only around the bolt fastening holes of the separator.
Even in this case, a short circuit due to the insertion of the bolt can be prevented, and a coating tube or the like is not required, so that the same effect as described above can be obtained.

The material of the separator 2 is not limited to resin and is not limited to flexible material.
Furthermore, the number of bolt fastening holes 4 is as shown in FIG.
Not limited to position. The positions and the numbers of the bolts and the bolt holes may be changed according to the size of the cells 3 and the number of stacked layers.

[0036]

Since the present invention is constructed and functions as described above, according to this, by inserting a bolt into a separator insulated from an electrode (cell portion), an insulating tube or the like is provided on the bolt. It is possible to prevent short circuits without coating, reduce the number of manufacturing processes by reducing parts, and reduce costs.In addition, it is possible to form bolt holes in every part of the separator part. Since the center of the cell and the like can be tightened with bolts, it is possible to efficiently apply surface pressure to the cell and to improve the power generation performance, which is an excellent effect that has never been obtained.

If the separator is made of resin and the separator is injection-molded to form the cell, the electrodes can be accurately positioned in the cell.
The insulation state during lamination becomes more reliable. Then, by using a resin that is a separator as a material having flexibility, an appropriate sealing effect can be exhibited. Further, since it is possible to absorb dimensional errors such as flatness and thickness of the cell during stacking, the position of the electrode (cell part) in the cell can be accurately arranged and rattling is suppressed. Therefore, the surface pressure of the cells can be equalized and the surface pressure itself can be increased to improve the power generation performance.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration in an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing details of the cell disclosed in FIG. 1; FIG. 2A is a diagram showing a cell formed by injection-molding a separator on an electrode.
(B) is the sectional view.

FIG. 3 is a schematic diagram showing a configuration of a fuel cell in a conventional example.

FIG. 4 is an explanatory diagram illustrating a direction in which a current of a fuel cell flows.

[Explanation of symbols]

1 electrode (cell part) 2 Separator (insulating resin) 3 cells 4 bolt fastening holes 5 bind plate 6 Protrusion for joining 7 convex

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeshi Ishikawa             300, Takatsuka-cho, Hamamatsu City, Shizuoka Prefecture Suzuki shares             In the company F term (reference) 5H026 AA06 BB00 CV06 CX08 EE18

Claims (4)

[Claims] 1. A cell comprising a plurality of electrodes arranged on the same plane so as to be insulated from each other through a separator, and a pair of separators being bonded together through an ion exchange membrane, wherein the electrode In a fuel cell formed by stacking a plurality of the cells so that the cells are connected in series, in the separator, a bolt fastening hole for inserting a bolt fastening the plurality of cells is formed, and a bolt fastening hole of the separator is formed. A fuel cell in which the periphery of the fuel cell is formed of an insulating member. 2. The fuel cell according to claim 1, wherein the separator is entirely made of an insulating material. 3. The separator according to claim 2, wherein the separator is made of resin, and the cell is formed by connecting the electrode and the separator by injection molding the separator. Fuel cell. 4. The fuel cell according to claim 3, wherein the resin, which is a material of the separator, is a flexible material.