JPH0888018A - Solid polymer fuel cell - Google Patents

Abstract

PURPOSE: To enhance sealing and power generating efficiency without largely increasing weight by installing a plurality of fastening means and fastening regions where a manifold part and a power generating part are located. CONSTITUTION: An end plate 21a is formed as a separating plate with a central plate 51 facing a power generating part and a frame-shaped plate 52 facing a manifold part. A fastening plate 23a has a plurality of taps passing through a part 61 in the direction of thickness, facing the central plate 51, of plate 21a, a bolt 62 is fixed to the tap, and pressure is applied to the power generating part by fastening the bolt 62 through the central plate 51. Fastening force is applied to the manifold part with a spring 25 and a bolt 26 through the frame-shaped plate 52. Fastening by the bolt 26 is adjusted to set fastening to the manifold part, and fastening by the bolt 62 is adjusted to set fastening to the power generating part. Without increasing the thickness of the fastening plate, suitable fastening is applied to the manifold part and the power generating part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer electrolyte fuel cell using a polymer ion exchange membrane as an electrolyte.

[0002]

2. Description of the Related Art As is well known, a polymer electrolyte fuel cell has a low operating temperature, a high output density and can be made compact and lightweight, and since the electrolyte is a solid, there is no loss, and the electrolyte is not corrosive. It has many advantages such as being durable.

By the way, in such a polymer electrolyte fuel cell, since the output voltage per unit cell is low, it is usually
As shown in FIG. 8, it has a laminated structure in which a plurality of unit batteries 1 are laminated.

The unit battery 1 has a frame member 2 for forming an oxidant passage, a cell containing frame member 3, a frame member 4 for forming a fuel passage, and a water permeable plate, each of which has a central portion removed to form an opening structure. The accommodating frame member 5, the water passage forming frame member 6, and the conductive separator plate 7 are provided so as to be laminated in the above order, and the opening 8 of the oxidant passage forming frame member 2 has a porous structure as shown in FIG. A flow distribution plate 9 made of a conductive conductive material is arranged, and a porous oxidizer electrode 1 is provided in an opening 10 of the cell housing frame member 3 as shown in FIG.
1, a three-layered cell 14 composed of a polymer ion exchange membrane 12 and a porous fuel electrode 13 is arranged, and a porous conductive material is used in the opening 15 of the fuel passage forming frame member 4 as shown in FIG. The formed flow distribution plate 9 is arranged, a water permeable plate (not shown) is arranged in the opening 16 of the water permeable plate accommodating frame member 5, and the opening 17 of the water passage forming frame member 6 has the same structure as shown in FIG. A conductive flow distribution plate (not shown) is formed, and each frame member and the conductive separator plate 7 are laminated in this state.

The oxidant passage forming frame member 2, the cell containing frame member 3, the fuel passage forming frame member 4, the water permeable plate containing frame member 5,
The water passage forming frame member 6 is made of an insulating material. In addition, each frame member and the conductive separator plate 7 are provided with an internal manifold for distributing and supplying the oxidant, fuel, and water to the oxidant passage, the fuel passage, and the water passage, which are formed by the frame member, and then discharging them. The constituent holes 18 are formed so as to overlap in the stacking direction.

A plurality of such unit cells 1 are stacked to form a fuel cell stack 20. Then, the conductive end plates 21 and 22 are applied to both end surfaces of the fuel cell stack 20 which are located in the stacking direction, and the outer surfaces of the end plates 21 and 22 are shown in FIGS. As shown, the tightening plates 23 and 24 wider than the end plates 21 and 22 are applied, and the tightening plates 23 and 24 are insulated from each other under the condition that the spring 25 is interposed at the peripheral portions of the tightening plates 23 and 24. It is tightened in the stacking direction at 26.

On the upper surface of the end plate 21, an oxidant supply pipe 27, a water supply pipe 28, and a fuel supply pipe which communicate with the internal manifold formed by the holes 18 in the peripheral portion of the fuel cell stack 20 are formed. 29, fuel discharge pipe 3
0, a water discharge pipe 31, and an oxidant discharge pipe 32 are erected in a state of being hermetically connected to a passage formed in the end plate 21. Further, the tightening plate 23 is provided with holes for penetrating the above-mentioned supply pipe and discharge pipe.

As can be seen from the above description, in this polymer electrolyte fuel cell, as shown in FIG. 11 (a), the power generation section 41 is located at the center surrounded by the broken line, and the power generation section 41 is A manifold portion 42 for distributing and supplying the fuel, the oxidant, and the water to the power generation portion 41 is located around the manifold portion 42.

However, the polymer electrolyte fuel cell thus constructed has the following problems. That is, the pressure of the internal manifold is 2 to 8 kg / cm ²
In the high-pressure polymer electrolyte fuel cell that is operated as
When the size of the power generation unit 41, that is, the size of the electrode is about 30 cm × 30 cm or more, the tightening force required for gas sealing in the manifold unit 42 is higher than the tightening force required for the power generation unit 41 in order to maintain the sealing performance. The total tightening force is 10 tons or more. When the peripheral portions of the tightening plates 23, 24 are tightened with such a large tightening force, the tightening plates 23, 24
The deformation (deflection) of 24 increases, and as a result, the power generation unit 4
There was a problem that the contact resistance of No. 1 becomes large and the power generation efficiency (power generation amount) is reduced. Therefore, it is conceivable to increase the thickness of the tightening plates 23 and 24 to reduce the deformation, but if this is done, it is unavoidable to increase the overall weight.

[0010]

As described above, in the conventional polymer electrolyte fuel cell, when it is attempted to obtain the sealing performance, the contact resistance of the power generation part increases and the power generation efficiency (power generation amount) increases. There was a problem of decline. Therefore, it is an object of the present invention to provide a polymer electrolyte fuel cell that can improve the sealing performance and the power generation efficiency without increasing the weight of the whole.

[0011]

In order to achieve the above object, in the present invention, a power generation section is located in the central portion, and a fuel, an oxidant, and a refrigerant are distributed to the power generation section around the power generation section. A fuel cell stack comprising a plurality of unit cells each including an element forming the power generation section and an element forming the manifold section so that the manifold section is located, and a unit cell formed by stacking the unit cells with a conductive separator interposed therebetween. A solid polymer electrolyte fuel cell comprising a tightening means for tightening a body in a stacking direction, wherein the tightening means tightens a first tightening means for tightening an area where the manifold section is located and a area where the power generating section is located. It is composed of a second tightening means.

[0012]

[Operation] First of tightening the area where the manifold is located
Second tightening means and a second area for tightening the area where the power generation section is located
It is possible to eliminate the interference with each other, and it is possible to perform the fastening with the fastening force suitable for each region without increasing the overall weight.

[0013]

Embodiments will be described below with reference to the drawings. FIG. 1 shows a fuel cell stack 20 incorporated in a polymer electrolyte fuel cell according to an embodiment of the present invention, and end plates 21a, 22 applied to both ends of the fuel cell stack 20 in the stacking direction. ing.

The fuel cell stack 20 has the same structure as the conventional one. The polymer electrolyte fuel cell according to this embodiment is different from the conventional one in the structure of the end plate 21a and the structure of the tightening plate 23a shown in FIG. Therefore, in the following figures, the same parts as those in FIGS. 8 to 11 are designated by the same reference numerals, and detailed description thereof will be omitted.

The end plate 21a is formed in a separating plate structure composed of a central plate portion 51 facing the power generation portion and a frame-shaped plate portion 52 facing the manifold portion described in FIG.

On the other hand, as shown in FIG. 2A, the tightening plate 23a is provided with a plurality of taps (not shown) penetrating in the thickness direction in a portion 61 of the end plate 21a which faces the central plate portion 51. Bolts 62 are attached to these taps, and the central plate portion 5 is tightened by tightening these bolts 62.
A pressing force, that is, a tightening force is applied to the power generation unit via 1. In addition, the tightening force is applied to the manifold portion by the spring 25 and the bolt 26 via the frame-shaped plate portion 52 as in the conventional case.

With such a configuration, the tightening force for the manifold portion can be set by adjusting the tightening force by the bolt 26, and the tightening force for the power generating portion can be set by adjusting the tightening force by the bolt 62. can do. That is, it is possible to apply a tightening force adapted to each of the manifold section and the power generation section without increasing the thickness of the tightening plate.

The present invention is not limited to the above embodiment. For example, as shown in FIG.
2 and the central plate portion 51 may be provided with a disc spring 63. Alternatively, as shown in FIG. 4, the bolt 62 is not used and the adjusting plate 64 is provided between the tightening plate 23 and the central plate portion 51. May be interposed. Further, as shown in FIG. 5, without using the bolt 62, a bellows 65 having a different shrinkage amount may be interposed between the tightening plate 23 and the central plate portion 51 and the frame-shaped plate portion 52.
Further, as shown in FIG. 6, without using the bolt 62, the disc spring 66 and the adjusting plate 6 are provided between the tightening plate 23 and the central plate portion 51.
7 may be interposed, or may be configured as shown in FIG.

3 to 5, reference numeral 68 denotes a disc spring, and in FIGS. 4 to 7, 69 denotes the central plate portion 51 and the frame-shaped plate portion 5.
2 shows a thin resin plate formed of ethylene tetrafluoride or the like or a thin metal plate formed of aluminum or the like, which is inserted in the boundary portion in order to absorb the difference in thickness between the two.

Further, in each of the above-mentioned examples, one end plate is composed of the central plate portion and the frame-shaped plate portion. However, both end plates have the same structure as described above, and the tightening force of the power generation portion is applied from both end plates. May be adjustable. It is also possible to provide a supply pipe and a discharge pipe for supplying and discharging the fuel, the oxidant, and the water to both end plates.

The water used for cooling the heat generated during power generation is not limited to this, but may be a boiling point close to the operating temperature of the fuel cell main body such as lower alcohol and fluorine-based inert liquid. Other refrigerants having (for example, 70 ° C to 100 ° C) may be used.

[0022]

As described above, according to the present invention,
Since the power generation part and the manifold part can be tightened with a tightening force adapted to them, it is possible to improve the sealing performance and the power generation efficiency without increasing the weight of the whole.

[Brief description of drawings]

FIG. 1 is a perspective view showing a fuel cell stack and an end plate incorporated in a polymer electrolyte fuel cell according to an embodiment of the present invention.

FIG. 2 (a) is a plan view of the same battery after assembly, and FIG. 2 (b) is a side view.

FIG. 3 is a diagram for explaining a first modified example of the present invention.

FIG. 4 is a diagram for explaining a second modified example of the present invention.

FIG. 5 is a diagram for explaining a third modified example of the present invention.

FIG. 6 is a diagram for explaining a fourth modified example of the present invention.

FIG. 7 is a diagram for explaining a fifth modified example of the present invention.

FIG. 8 is a perspective view showing a fuel cell stack and an end plate incorporated in a conventional polymer electrolyte fuel cell.

FIG. 9 is a perspective view of a distribution plate incorporated in the battery.

FIG. 10 is a perspective view of a cell incorporated in the battery.

FIG. 11 (a) is a plan view of the battery after assembly, and FIG. 11 (b) is a side view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Unit battery 2 ... Oxidizing agent passage formation frame material 3 ... Cell accommodation frame material 4 ... Fuel passage formation frame material 5 ... Water permeable plate accommodation frame material 6 ... Water passage formation frame material 7 ... Conductive separator plate 8 , 10, 1
5, 16 and 17 ... Opening portion 9 ... Flow distribution plate 14 ... Cell 18 ... Hole 20 ... Fuel cell stack 21, 21a, 22 ... End plate 23, 23a,
24 ... Tightening plate 26 ... Bolt 27 ... Oxidant supply pipe 28 ... Water supply pipe 29 ... Fuel supply pipe 30 ... Fuel discharge pipe 31 ... Water discharge pipe 32 ... Oxidant discharge pipe 41 ... Power generation part 42 ... Manifold part 51 ... Power generation Central plate part 52 facing the part 52 ... Frame-shaped plate part facing the manifold part 62 ... Bolts 63, 66 ... Disc springs 64, 67 ... Adjusting plate 65 ... Bellows

Claims (2)

[Claims] 1. An element constituting the power generation section such that a power generation section is located in a central portion, and a manifold section for distributing and supplying a fuel, an oxidant, and a refrigerant to the power generation section is located around the power generation section, and Solid polymer type including a fuel cell stack formed by stacking a plurality of unit cells each including an element forming a manifold part through a conductive separator, and a tightening unit that tightens the fuel cell stack in the stacking direction. In the fuel cell, the tightening means includes a first tightening means for tightening an area where the manifold portion is located and a second tightening means for tightening an area where the power generating portion is located. Polymer electrolyte fuel cell. 2. An element constituting the power generation section such that a power generation section is located at a central portion, and a manifold section for distributing and supplying fuel, an oxidant, and a refrigerant to the power generation section is located around the power generation section, and A fuel cell stack formed by stacking a plurality of unit cells each including an element constituting a manifold part with a conductive separator interposed between the unit cell and the fuel cell stack. A pair of end plates provided with a flow path communicating with the flow path of the manifold section, a pair of tightening plates applied to the outer surfaces of the end plates, and a tightening means for applying a tightening force between the pair of tightening plates. In the polymer electrolyte fuel cell including at least one of the pair of end plates, at least one of the end plate has a central plate portion facing the power generation portion and the manifold portion. It is formed in a separation plate configuration that is separated into a facing frame-shaped plate portion, and adjusts the tightening force in the region where the power generation part is located between the central plate part and the one tightening plate adjacent to the center plate part. A polymer electrolyte fuel cell having a tightening force adjusting mechanism.