JP2000012067A - Solid polymer electrolytic fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely and easily position cells constituting a fuel cell layered product. SOLUTION: In a single cell 13, constituted by nipping a fuel cell 1 having an electrolytic layer 1A and a fuel electrode 1B and oxidizer electrode 1C arranged on both sides thereof between separators 2A, 2B, the tip pin 25 of a holding pin 20 inserted to a holding pin insert-side holding hole 11 and a snap ring insert-side holding hole 12 and combined with a snap ring 10 to hold the cell 13 is protruded from the outer surface of the separator 2B, and it is fitted to a pin tip insert hole 25 provided on the end of the holding pin 20 of the adjacent cell 13 to laminate the cell 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid polymer electrolyte fuel cell which uses a solid polymer electrolyte membrane as an electrolyte layer to obtain electric energy by an electrochemical reaction.
In particular, the present invention relates to a configuration that facilitates stack assembly of unit cells.

[0002]

2. Description of the Related Art Fuel cells include a solid polymer electrolyte type, a phosphoric acid type, a molten carbonate type, and a solid oxide type depending on the type of electrolyte used. Among them, the solid polymer electrolyte fuel cell is a fuel cell utilizing the fact that when a polymer resin membrane having a proton exchange group in a molecule is saturated with water, it exhibits a low resistivity and functions as a proton conductive electrolyte membrane. is there.

FIG. 7 is an exploded sectional view showing the structure of a unit cell of a typical conventional solid polymer electrolyte fuel cell. FIG. 8 is an exploded perspective view of the present cell. 7 and 8, a fuel cell 1 has an electrolyte layer 1A made of a thin rectangular solid polymer electrolyte membrane, and this electrolyte layer 1A.
A fuel electrode 1B closely adhered to one surface of the fuel cell 1A and an oxide electrode 1C closely adhered to another surface of the electrolyte layer 1A
Consisting of Among them, the fuel electrode 1B and the oxide electrode 1C
Both include a catalyst layer containing a catalyst active material, an electrode substrate that supports the catalyst layer, and supplies and exhausts a fuel gas or an oxidizing gas to the catalyst layer, and also functions as a current collector. And is joined to the main surface of the electrolyte layer 1A by hot pressing.

[0004] The separator 2A and the separator 2B, which are disposed with the fuel cell 1 interposed therebetween, are both formed of a gas impermeable material. Among them, a plurality of convex partition walls 4A are provided on a surface of the separator 2A disposed outside the fuel electrode 1B facing the fuel electrode 1B, and the tops thereof are adjacent to each other by being assembled in contact with the fuel electrode 1B. A gas flow groove 3A is formed between the two convex partition walls 4A. That is, the fuel gas supplied to the fuel electrode 1B is introduced from an inlet provided at one end of the separator 2A as shown in FIG.
And the remaining gas not contributing to the reaction is collected and discharged to a discharge port provided at the other end. A cooling water flow groove 6A is formed between the plurality of convex partition walls 7A provided on the outer surface of the separator 2A, and the cooling water for maintaining the separator 2A and the fuel cell 1 at a constant temperature flows therethrough. Swept away. Similarly, the surface of the separator 2B facing the oxide electrode 1C is provided with the provided convex partition 4B.
A gas flow groove 3B is formed between the holes, and an oxidizing gas supplied to the oxide electrode 1C flows. Further, a cooling water flow groove 6B is formed on the outer surface between the provided convex partition walls 7B, and the cooling water flows like the separator 2A.

[0005] The gas seals 5 provided at the peripheral portion of the gas flow groove 3A of the separator 2A and the peripheral portion of the gas flow groove 3B of the separator 2B are provided with a fuel gas or an oxidizing gas flowing through these flow regions. It functions to prevent leakage to the outside. Further, the cooling water seal body 8 has a function of preventing leakage of the cooling water flowing through the cooling water flow grooves 6A and 6B.

[0006] The holding pins 9 shown in the figure serve to hold a unit cell 13 formed by sandwiching the fuel cell 1 between the separator 2A and the separator 2B. The holding pins 9 are separated from the separator 2 </ b> A
, The through hole of the fuel cell 1, and the retaining ring 1 of the separator 2B.
2, the retaining ring 10 is inserted from the side of the retaining ring insertion side retaining hole 12, and the retaining pin 9 is fitted into the retaining ring insertion groove 23, thereby holding the unit cell 13.

[0007] The voltage generated by the unit cell 13 configured as described above is a low value less than 1 (V). Therefore, when a solid polymer electrolyte fuel cell is put to practical use, a large number of cells 13 are stacked to form a fuel cell stack, which is used as a series connection of the cells with a high generated voltage. FIG. 9 is a side view schematically showing a configuration of a fuel cell stack of a typical solid polymer electrolyte fuel cell.
As shown in the figure, a plurality of unit cells 13 formed by sandwiching a fuel cell unit between a set of separators are sequentially stacked, and at both ends thereof, a current collector plate 14 for extracting a generated direct current, and a unit An electric insulating plate 15 for electrically insulating the battery 13 and the current collecting plate 14 from the supporting structure is provided, and a tightening plate 16, a tightening bolt 17, and a conical spring for tightening are provided on the side thereof. 18, a suitable pressing force is applied by a fastener 19 to be tightened and held. In order to prevent the gas flow groove of the cell 13 from being blocked by the moisture contained in the reaction gas supplied by humidification, the flow direction of the gas flowing through the gas flow groove is set to be the direction of gravity. The cells 13 are arranged and installed.

[0008]

As described above, in the conventional solid polymer electrolyte fuel cell, a predetermined number of unit cells 13 formed by sandwiching fuel cells between a pair of separators are stacked. A stacked body is formed, and a fuel gas and an oxidizing gas are supplied to obtain DC power of a predetermined generated voltage. However, such a solid polymer electrolyte fuel cell still has the following problems.

That is, in the above configuration, the unit cell 13 formed by holding the fuel cell unit by a set of separators and holding the unit by the holding pin 9 and the retaining ring 10 is a substantially rectangular flat plate. When stacking the batteries 13, the cells 13 are placed with the surface on which the cooling water flow grooves are arranged downward,
The next unit cell 13 is placed thereon while adjusting the position by visual observation and hand alignment based on the side of the side, and the next unit cell 13 is further placed thereon while adjusting the position in the same manner. Many unit cells 13 are stacked. Therefore, in the solid polymer electrolyte fuel cell of this configuration,
With the increase in the number of unit cells to be stacked, a shift is likely to occur in the stacking position of the unit cells adjacent to each other, and the combination of the gas seal unit and the cooling water seal unit formed between the units becomes insufficient. There is a possibility that the reaction gas or the cooling water leaks, the cell characteristics are reduced, or the fuel cell stack is damaged.

[0010] An object of the present invention is to provide a fuel cell stack in which the alignment of adjacent cells can be carried out reliably and easily when assembling a fuel cell stack. An object of the present invention is to provide a highly reliable solid polymer electrolyte fuel cell that can operate stably without causing leakage of a reaction gas or cooling water.

[0011]

In order to achieve the above object, the present invention provides a fuel cell in which a fuel electrode and an air electrode are disposed on both main surfaces of an electrolyte layer comprising a solid polymer electrolyte membrane. A fuel cell is formed by sandwiching a cell between a separator having a fuel gas passage on its inner surface and a separator having an air passage on its inner surface to form a unit cell, and by stacking a plurality of such unit cells. In a solid polymer electrolyte fuel cell including a battery stack, (1) a pin insertion hole penetrating in a stacking direction in a unit cell, and a holding pin inserted into the pin insertion hole from an outer surface of one separator. And a retaining ring that is inserted from the outer surface of the opposing separator and that is inserted into a retaining ring insertion groove provided in the retaining pin. A protrusion protruding, and further comprising a single cell stack positioning means comprising a recess of the cell holding unit of cells that are adjacent are fitted into the convex portion.

(2) Further, the unit cell is provided with unit cell stacking positioning means comprising a concave portion formed on the outer surface of the separator and a positioning member fitted into the concave portion, for example, separated from the separator. The cooling water passage forming member provided is used as a positioning member, and is assembled by fitting into a cooling water passage forming member insertion recess formed on the outer surface of the separator.

According to the above configuration (1), the projections of the cell holding means projecting in the stacking direction of the cells assembled and held by the cell holding means consisting of the holding pin and the retaining ring are adjacent to each other. Since the cells are stacked by fitting them into the recesses of the cell holding means of the cells, there is no need to stack the cells while adjusting the position by visual inspection and manual adjustment as in the conventional case. Can be configured.

Also, in the case of the configuration as described in the above (2), the unit cells are stacked by fitting the positioning members into the concave portions formed on the outer surfaces of the separators of the unit cells adjacent to each other, so that the cells are properly stacked. Thus, the fuel cell stack is easily formed.

[0015]

<Embodiment 1> FIG. 1 is an exploded sectional view showing the structure of a unit cell of a solid polymer electrolyte fuel cell according to a first embodiment of the present invention, and FIG. It is an exploded perspective view. FIG. 3 is a partial cross-sectional view of the fuel cell stack showing the stacked state of the unit cells. In these figures, components having the same functions as the components used in the unit cells of the conventional example shown in FIGS. 7 and 8 are denoted by the same reference numerals, and redundant description will be omitted.

The difference between the structure of the present embodiment and the structure of the conventional example is that the fuel cell 1 is divided into a separator 2A and a separator 2B.
In the structure of the holding pin 20 of the unit cell holding means used for holding and holding the battery. That is, as shown in FIG. 7, the holding pin 9 having the retaining ring insertion groove 23 at the distal end is used in the configuration of the conventional example, whereas the holding pin 20 used in the configuration of the present embodiment is used. Has a retaining ring insertion groove 23
The pin tip 25 is coaxially machined with the insertion pin 24, has a moderately small diameter, and has a chamfered tip.
Is provided at the opposite end thereof with a pin tip 2
5 is provided with a pin tip insertion hole 26 to be fitted. In this configuration, the holding pin 20 is inserted into the holding pin insertion side holding hole 11 of the separator 2A, the through hole of the fuel cell unit 1, and the retaining ring insertion side holding hole 12 of the separator 2B.
Into the retaining ring 1 from the retaining ring insertion side holding hole 12 side.
Is inserted into the retaining ring insertion groove 23 of the retaining pin 20 to hold the unit cell 13, the pin tip 25 of the retaining pin 20 is inserted into the separator 2B in the stacking direction from the retaining ring insertion side retaining hole 12 of the separator 2B. Will be arranged so as to protrude from the outer surface. Therefore, when forming a fuel cell stack by stacking a plurality of unit cells, as shown in FIG.
Since the pin tips 25 of the holding pins 20 protruding from the outer surface of the separator 2B are fitted into the pin tip insertion holes 26 of the holding pins 20 incorporated in the adjacent cells, the stacking is performed. And easily.

<Embodiment 2> FIG. 4 is an exploded sectional view showing the structure of a unit cell of a solid polymer electrolyte fuel cell according to a second embodiment of the present invention, and FIG. 5 is an exploded perspective view of the unit cell. is there. FIG. 6 is a partial cross-sectional view of the fuel cell stack showing the stacked state of the unit cells. Also in these figures, components having the same functions as those of the components used in the unit cells of the conventional example shown in FIGS. 7 and 8 are denoted by the same reference numerals, and redundant description will be omitted.

The feature of this embodiment is that the separator 2
A counterbore groove 22 for cooling water plate is provided on the outer surface of A, 2B, that is, a surface opposite to the surface in contact with the fuel cell 1, and the cooling water groove plate 21 is fitted into the counterbore groove 22 for cooling water plate. Thus, a flow path of cooling water for cooling the separators 2A and 2B and the fuel cell 1 is formed. The cooling water groove plate 21 has a plurality of partition walls 7A extending parallel to one surface, and a plurality of partition walls 7A extending parallel to the other surface.
B, and the fuel cell 1 is
A and 2B are sandwiched by the holding pin 9 and the retaining ring 10, and the unit cells 13 formed by fitting the cooling water groove plate 21 into the cooling water plate counterbore 22 and stacking them are stacked.
A and the top of the partition wall 7B are disposed in contact with the bottom surface of the counterbore groove 22 for the cooling water plate, and are formed between the cooling water flow groove 6A formed between the adjacent partition walls 7A and the adjacent partition wall 7B. The cooling water flows through the cooling water flow groove 6B to cool the unit cells.

In this configuration, the counterbore groove 22 for the cooling water plate is provided.
The fuel cell stack is constituted by stacking the unit cells 13 by fitting the cooling water groove plate 21 to the fuel cell, so that there is no misalignment between adjacent unit cells, and it is possible to assemble properly and easily. it can. In this embodiment, the cooling water groove plate 21 is fitted to the cooling water plate counterbore 22. However, the present invention is not limited to this configuration. A separate recess is provided on the outer surface of the separator, and a positioning member is provided in the recess. Similarly, the unit cells can be stacked properly and easily without causing a positional shift even when the unit cells are stacked.

[0020]

As described above, according to the present invention, (1)
Since the solid polymer electrolyte fuel cell is configured as described in claim 1, a positioning function when the fuel cells are assembled by stacking the cells is provided, and a large number of cells are stacked. Even when a fuel cell stack is used, stacking can be performed properly and easily, and a highly reliable solid polymer electrolyte fuel cell that can operate stably without leakage of reaction gas or cooling water can be obtained. It was obtained.

(2) Even when the solid polymer electrolyte fuel cell is constructed as in claim 2 or 3, since a positioning function for assembling the fuel cell stack is similarly provided, It is suitable as a solid polymer electrolyte fuel cell that can be stacked appropriately and easily and can operate stably without leakage of reaction gas or cooling water.

[Brief description of the drawings]

FIG. 1 is an exploded sectional view showing a configuration of a unit cell of a first embodiment of a solid polymer electrolyte fuel cell according to the present invention.

FIG. 2 is an exploded perspective view of the unit cell of the first embodiment.

FIG. 3 is a partial cross-sectional view of a fuel cell stack showing a stacked state of the unit cells of the first embodiment.

FIG. 4 is an exploded cross-sectional view showing the configuration of a unit cell according to a second embodiment of the solid polymer electrolyte fuel cell of the present invention.

FIG. 5 is an exploded perspective view of a unit cell according to a second embodiment.

FIG. 6 is a partial cross-sectional view of a fuel cell stack showing a stacked state of the unit cells of the second embodiment.

FIG. 7 is an exploded cross-sectional view showing a configuration example of a unit cell of a conventional solid polymer electrolyte fuel cell.

8 is an exploded perspective view of the unit cell of the conventional solid polymer electrolyte fuel cell shown in FIG.

FIG. 9 is a side view schematically showing a configuration example of a fuel cell stack of a typical solid polymer electrolyte fuel cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel cell 1A Electrolyte layer 1B Fuel electrode 1C Oxidizer electrode 2A, 2B Separator 3A, 3B Gas flow groove 5 Gas seal body 6A, 6B Cooling water flow groove 8 Cooling water seal body 10 Retaining ring 11 Retaining pin insertion side Holding hole 12 Retaining ring insertion side holding hole 13 Single cell 20 Retaining pin 23 Retaining ring insertion groove 25 Pin tip 26 Pin tip insertion hole

Claims (3)

[Claims] 1. A fuel cell in which a fuel electrode and an air electrode are disposed in close contact with both main surfaces of an electrolyte layer comprising a solid polymer electrolyte membrane, a separator having a fuel gas passage on the inner surface and a fuel cell on the inner surface. A solid polymer electrolyte fuel cell comprising a fuel cell stack formed by stacking a plurality of the unit cells by sandwiching the unit cells with a separator having an air passage, A battery, a pin insertion hole penetrating in the stacking direction, a holding pin inserted into the pin insertion hole from the outer surface of one separator, and a retaining ring insertion groove provided in the holding pin inserted from the outer surface of the opposite separator. A retaining ring consisting of a retaining ring incorporated into the unit cell, a projection protruding in the stacking direction from the outer surface of the separator provided on the unit cell retaining unit, and a unit cell retaining unit of an adjacent unit cell. , The protrusion Solid polymer electrolyte fuel cell characterized by comprising a single cell stack positioning means comprising a fitting recess fitted. 2. A fuel cell in which a fuel electrode and an air electrode are closely attached to both main surfaces of an electrolyte layer comprising a solid polymer electrolyte membrane, a separator having a fuel gas passage on the inner surface and a fuel cell on the inner surface. A solid polymer electrolyte fuel cell comprising a fuel cell stack formed by stacking a plurality of the unit cells by sandwiching the unit cells with a separator having an air passage, A battery, a recess formed on the outer surface of the separator,
A solid polymer electrolyte fuel cell comprising unit cell stacking positioning means comprising a positioning member fitted into the recess. 3. The solid polymer electrolyte fuel cell according to claim 2, wherein the positioning member of the unit cell stacking positioning means is a cooling water passage forming member separated from a separator. The concave portion of the battery stacking positioning means,
A solid polymer electrolyte fuel cell, comprising a concave portion formed on an outer surface of the separator for inserting a cooling water passage forming member.