JPS5975567A - Fuel cell - Google Patents

Abstract

PURPOSE:To maintain air tightness and obtain a fuel cell that improves performance life span by doubly insert a sealed packing between a cell stack and a manifold and providing a recess or a protrusion that prevents its positioning shift in the cell stack and manifold. CONSTITUTION:A fuel cell is formed on the external surface of a cell stack 101 laminated with an element cell, interconnector, etc. by arranging a metallic manifold 104 for supplying and exhausting reaction gas through double non-end type teflon sealed packings 102 and 103. Recesses 105 and 108 that prevent the positioning shift of the packings are provided at the periphery on the external surface of the cell stack 101 and at the mounting edge 107 in the periphery of the manifold 104. In addition, hooking protrusions 106 and 109 are formed at the packings 102 and 103 and are engaged with the said recesses 105 and 108. As a result, the airtightness between the cell stack 101 and packing 102 is held highly and the fuel cell that prevents the positioning shift of the sealed packings 102 and 103 can be comprised.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to fuel cells, and more particularly to improvement of a seal between a cell stack and a reactant gas supply/discharge manifold disposed on the outer peripheral surface of the cell stack.

[Technical background of the invention]

2. Description of the Related Art Fuel cells are conventionally known as devices that directly convert energy contained in fuel into electrical energy. Typically, a fuel cell with this method has a pair of porous electrodes sandwiching an electrolyte, and a gaseous fuel such as hydrogen is brought into contact with the back surface of one of the electrodes.
The back surface of the other electrode is brought into contact with a gaseous oxidizing agent such as air, and the electrochemical reaction that occurs at this time is used to extract electrical energy from between the two electrodes.

FIGS. 1 and 2 show the schematic structure of a fuel cell, and numeral 1 in the figures is a unit cell. This unit cell 1 is formed by placing a matrix impregnated with, for example, phosphoric acid (H, PO4) as an electrolyte in the center, and two porous electrodes made of carbon material to which a catalyst is added on both sides. There is. An interconnector 2 is arranged on the back side of both electrodes of this unit cell, and flow paths for liquid fuel and a fluid oxidizer are formed between the unit cell 1 and the interconnector 2.

This ink connector 2 is a plate with lips made of a mixed bond of graphite and thermosetting resin. A combination of the unit cell 1 and the interconnector 2 constitutes one unit battery, and a plurality of such unit batteries are stacked. And on the top and bottom there are bowl boards 3.
are arranged, a tightening plate 5 is arranged through an insulating spacer 4, and a prismatic cell stack 6 is attached by tightening metal fittings etc.
is configured. Fluid flow ports are provided on the outer circumferential surface of the cell stack 6, and Teflon rubber holes are provided on the four outer circumferential surfaces of the cell stack 6. A metal manifold 8 is installed for supplying or discharging a reaction gas through an insulating seal gasket 7 such as a gasket. These manifolds 8 form a reaction gas flow path between the outer surface of the cell stack 6 and the seal gasket 7 maintains airtightness within the manifold 8, and furthermore, the seal gasket 7 maintains airtightness between the cell stack 6 and the manifold 8. This is to maintain safety and corrosion resistance by electrically insulating between the

FIG. 3 shows the mounting portion of the manifold 8, and the peripheral edge of the manifold 8 is formed with a recessed edge 9 for the cell stack 6. As shown in FIG. In addition, this mounting edge 9 is provided with one or more protrusions 10 (the figure shows an example of two protrusions) on the surface facing the cell stack 6.
0 is brought into pressure contact with the seal packing 7 to ensure airtightness.

[Problems with background technology]

The operating temperature of the cell stack 6 is as high as 170°C to 200°C. At this time, since the cell stack 6 and the metal manifold 8 are made of different materials and have different coefficients of thermal expansion, there is a mutual difference between the cell stack 6 and the sheet/L/nox skin 7, and between the manifold 8 and the seal packing 7. When sliding occurs due to the difference in thermal expansion, there is a risk of deterioration of moldings, etc. in the seal packing due to contact friction at that time./1. . J, Puko'I'L;h Kakawajin carving, For:
, :j years old 1'+15 fitノ, the height of the cell stack 6 is 3 m, so the cell stack 6
The difference in the amount of thermal expansion in the height direction between and manifold 8 is 20 to 4
It is expected that the distance will reach 0 m, and as a result, there is a risk that the seal packing 7 will come off the mounting edge of the manifold 8 and the airtightness will be impaired.

On the other hand, the inside of the cell stack 6 is filled with nitrogen gas so that the J, ;/, reaction gas in the manifold 8 does not flow into the inside of the cell stack 6 and mix the oxidizing agent and m old. Furthermore, the interior of the manifold is slightly pressured to prevent reaction gas from flowing into the manifold. Therefore, if the seal gasket 7 deteriorates, nitrogen gas in the cell stack 6 will flow out to the manifold 8, resulting in a situation where the gas seal gas has deteriorated and must be replaced, which may further shorten the life of the fuel cell. there were.

[Purpose of the invention]

The present invention was made based on these circumstances, and
The purpose is to maintain airtightness between the cell stack and the manifold, and to provide a fuel cell with high performance, long life, and high reliability.

[Summary of the invention]

In the fuel cell of the present invention, Teflon seal packing is inserted in a double layer between the outer peripheral surface of the cell stack and the peripheral edge of the manifold, and the cell stack and the manifold each have a recess for preventing displacement. Or by providing a convex part,
It is designed to cause sliding only between the seal packing on the cell stack side and the seal packing on the manifold side.〇 [Embodiment of the invention] Figures 4 and 5 show the first embodiment of the invention. 101 in the figure is a prismatic cell stack formed by laminating a plurality of unit cells, ink connectors, etc. On the four outer surfaces of the cell stack 101, there are Teflon-based seal packings 102 with excellent heat resistance, corrosion resistance, and electrical insulation properties.
103 are arranged in a double layered manner, and a fully bent manifold 104 for supplying and discharging the reaction gas is arranged via these mats and links 102 and 103 to form a combustion chamber and a pond. ing. FIG. 5 shows a seal between the cell stack 101 and the manifold 104.
At the peripheral end of the outer circumferential surface of 01, a gap P7E1θ5 for preventing gasket displacement is provided in an endless manner at a portion in contact with the seal gasket 102. Further, as the seal packing 102 in contact with the cell stack 101, a flexible material, for example, sponge-like or marshmallow-shaped, is used. A mating protrusion 106 is formed in advance.

On the other hand, a cell stack 10 is provided at the periphery of the manifold 104.
1 is formed. Also, on the surface of the mounting edge 107 facing the cell stack 101, an endless recess 108 is provided for preventing positional displacement of the seal at the part where the seal gasket 103 contacts, and the seal gasket 103 that contacts the manifold 104 has an endless recess 108. Engagement protrusions 109 that fit into the four parts 10B are formed in advance. Note that the seal packing 1 in contact with the manifold 104
As 03, hard Teflon rubber or a Teflon plate is used.

This ensures an electrically insulating gap between the manifold 104 and the ink connector in the cell stack 101 when the manifold 104 is in pressure contact with the ink connector, and also prevents the compressive force on the seal packing 103 from fluctuating due to temperature changes. This is to prevent permanent deformation of the seal 103.

According to the above configuration, the recess 105 for preventing displacement of the knob is provided at the peripheral end of the outer peripheral surface of the cell stack 101,
The engaging protrusion 1 of the seal packing 102 is placed in the recess 105 with the seal packing 102.
06, the outer peripheral surface of the cell stack 101 is not a smooth surface due to the stacking of unit cells, interconnectors, etc., but the seal and seal are formed with the cell stack 101.
The airtightness between the gasket 102 and the seal gasket 102 is maintained to a high degree, and there is no possibility that the seal gasket 102 will be misaligned. Manifold 1
Similarly, the relationship between the seal 04 and the seal 103 is kept airtight, and misalignment is also prevented.

Therefore, due to the difference in the amount of thermal expansion between the cell stack 101 and the manifold 104, the seals and the gaskets 102 and 103 will slide together.
Since both θ3 and θ3 are made of Teflon, their sliding is extremely smooth. Since both the gaskets 102 and 103 are in close contact with each other and are slid together, the airtightness will not be compromised by 1β, and furthermore, deterioration such as cracks will not occur. 1
between the cell stack 101 and the seal packing 102;
There is also a difference in the amount of thermal expansion between the manifold 104 and the seal packing 103, but these differences are due to the difference in the seal portion <? Since they are absorbed by the elasticity of the covers 102 and 103, there is no problem. Moreover, as a result of the difference in the amount of thermal expansion, the seal packings 102 and 103 are different from each other in the recesses 105 of the cell stack 101 and the manifold 104, respectively.
, 10B, the effect of improving the airtightness is obtained.

Note that the present invention is not limited to the above embodiments. For example, the width of the mounting section 1070 provided on the manifold 104 may be appropriately set depending on the difference in the amount of thermal expansion between the cell stack 10 and the manifold 104. That is, in large-sized fuel cells, the difference in the amount of thermal expansion is large, so it is necessary to increase the width of the mounting edge 107. FIG. 6 shows a second embodiment of the present invention in which the mounting edge 107 is widened.

In addition, 11Cf sealing agent (
For example, by applying Parflon paste (product name), both 1? The contact resistance between the gaskets 102 and 103 is reduced, and the two gaskets 102 and 103 can be slid together more smoothly.

Furthermore, the above-mentioned No. 1. In the second embodiment, the cell stack 10
1. The concave portions 105 and 108 for preventing gasket displacement, which are provided at each of the five positions of the manifold 104, may be used as convex portions for preventing gasket displacement. In this case, the seal packing 102° 10B may be formed with a recess that fits into the protrusion for preventing displacement, but the seal/? If the cover is highly flexible, it can easily fit into the misalignment prevention recesses or protrusions by pressing against the cell stack 101 or manifold 104 without having to provide the engaging protrusions 106, 109 or recesses in advance. and maintain airtightness. Furthermore, although the recesses or protrusions for preventing gasket displacement are provided at the portions where the seal gaskets 102 and 103 come into contact, they do not necessarily have to be endless; Alternatively, it may be a large number of recesses.

Alternatively, a plurality of seal packings 102 on the cell stack 101 side and a plurality of seal packings 103 on the manifold 104 side may be provided.

In this case, the number of concave portions or convex portions for preventing the seal from shifting does not necessarily have to match the number of the four seals.

〔Effect of the invention〕

As described above, according to the present invention, Teflon-based seals and seals are inserted between the cell stack and the manifold in a double layered manner, and the cell stack and the manifold each have 74 seals and four parts for preventing displacement. By providing the convex portion, the seal packing on the cell stack side and the seal packing on the manifold side only slide together, thereby maintaining airtightness between the cell stack and the manifold. This makes it possible to provide fuel cells with high performance, long life, and high reliability.

[Brief explanation of drawings]

1 to 3 show a conventional example, in which FIG. 1 is a longitudinal cross-sectional view, FIG. 2 is a plan view, and FIG. 3 is a cross-sectional view showing a seal portion between a cell stack and a manifold. 4 and 5 show a first embodiment of the present invention, in which FIG. 4 is a plan view of a fuel cell, and FIG. 5 is a cross-sectional view showing a seal portion between a cell stack and a manifold. - Figure 6 is the second embodiment of the present invention.
FIG. 3 is a cross-sectional view of a seal portion between a cell stack and a manifold, showing an example. 1...Battery, 2...Interconnector, 6, 10
1...Cell stack, 7,102,103...Seal packing, 8,104...Manifold, 105゜1
08...Four parts to prevent Nokutsukin from shifting. Applicant's agent Patent attorney Takehiko Suzue Figure 2
. ( 3rd evil 8 Fig. 4

Claims (7)

[Claims] (1) A cell stack formed by laminating a plurality of unit cells, interconnectors, etc., and a reactive gas supply/discharge system arranged on the outer circumferential surface of this cell stack to form a reactive gas flow path between the cell stack and the outer circumferential surface of the cell stack. a manifold for use in the cell stack, an endless Teflon-based sealing packing inserted in a double layer between the peripheral edge of the manifold and the outer peripheral surface of the cell stack, and a surface in contact with each sealing packing of the cell stack and the manifold. A formed in? 1. A fuel cell characterized by comprising a concave portion or a convex portion for preventing misalignment of the fuel cell. (2) The fuel cell according to claim (1), wherein the seal packing on the cell stack side is soft, and the seal nozzle and packing on the manifold side are hard. (3) The fuel cell according to claim (1), characterized in that at least one of the seal packings on the cell stack side and the seal packings on the manifold side is plural. (4) The fuel cell according to claim (1), characterized in that the seal packing is pre-formed with a portion that fits into a concave portion or a convex portion for preventing displacement of the seal packing. (5) The fuel cell according to claim (1), characterized in that the seal/gut skin is made to fit into the concave portion or convex portion for preventing the seal from shifting due to its flexibility. (6) The four parts or convex parts for preventing the seal from shifting are provided endlessly along each sealing surface of the cell stack and the manifold.
) The fuel cell described in section 2. (7) A fuel cell according to claim (6), characterized in that a plurality of concave portions or convex portions for preventing gasket displacement are provided.