JPS58157063A - Sealing of layer-built fuel cell - Google Patents

Abstract

PURPOSE:To obtain highly reliable sealing parts between each unit cell and gas-seaparating plates by positioning fusible sealing members which are resistant to both high temperature and phosphoric acid between each unit cell and gas- separating plates, and fusing the sealing members to the unit cells and the gas- separating plates by performing heat treatment. CONSTITUTION:One of the tetrafluoroethylene-hexafluoroethylene copolymer and the perfluoroalkyl-vinylether copolymer is used as a sealing member. After fuel- side sealing members 15 and 15 are placed on the sealing surface 16' of a gas- separating plate 1', a fuel cell 14 is positioned between the sealing members 15 and 15, and placed on the gas-separating plate 1'. Next, an electrolyte matrix 13 is placed on the fuel cell 14, an oxidizer electrode 12 and sealing members 11 are stacked over the electrolyte matrix 13, and another gas-separating plate 1 is placed over the sealing members 11, thereby forming a unit body. Then, after assembling a layer-built fuel cell by repeatedly performing such a work as above, pressure is applied in the stacked direction of the fuel cell. After that, the fuel cell is subjected to heat treatment in an atmosphere of an inactive gas or the like so as to fuse the sealing members 11 and 15 to the unit cells and the separating plates 1, thereby forming sealing parts.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of sealing a gas separation plate and a unit cell in a stacked fuel cell.

Conventionally, this type of fuel cell was shown in Figure 1. In Figure 1, ([1)' is a gas separation plate, (Odor is a gasket for sealing the oxidizer electrode, (3) is an oxidizer electrode, ( 4
) is the electrolyte matrix, C6) is the fuel electrode, oxidizer vt electrode (3), electrolyte matrix 14), fuel electrode (
6) constitutes a single cell, and (6) is a gasket for sealing the fuel electrode. Figure 2 shows a stack of units (1) to (6) in Figure 1, (11 is an insulating plate, (8)
191 is a current collector plate, 191 is a laminate of multiple laminated bodies, (
101 is air as an oxidizing agent (the river is a fuel).

Next, the operation will be explained. Gas separation plate (1), (1γ
1-, electrodes, gaskets, and electrolyte matrix are laminated in the order shown in FIG. That is, the oxidizing agent electrode (3) is fitted inside the oxidizing agent electrode (a gasket with a wide frame shape of horse mackerel).
The electrolyte matrix (4) is superimposed on this, and the fuel v
The fuel electrode (6) fitted inside the window frame-shaped gasket (6) of the t-pole (6) is soldered. This point? Ij
kv, and stack several unit bodies as shown in Figure 2 to assemble a stacked fuel cell. M After making, empty% 110
1 and fuel (11) are supplied and output is output from the current collector plate (8) to operate the battery.

Conventional stacked fuel cells are constructed as described above, so in order to seal the gas and liquid between the gas separation plate and the single cell, the thickness of both electrodes and their respective gaskets are laminated. The thickness had to be the same, and the thickness had to be designed based on the material constants of the electrode and gasket. In addition, fluororubber-based materials are used as gaskets because they require considerable elasticity, but they have drawbacks such as severe deterioration in batteries that use phosphoric acid electrolytes at high temperatures, making it difficult to maintain long-term sealing properties. was there.

This invention was made to eliminate the drawbacks of the conventional gaskets as described above, and each gasket is made of FEP (tetrafluoroethylene-hexafluoropropylene copolymer) or PFA (perfluoropropylene copolymer). Alki μ vinyl
By using a material that can withstand high-temperature phosphoric acid and can be melted and molded, such as ATEμ material, the V − between the gas separation plate and the cell is
The purpose is to provide sealing performance for stacked fuel cells that perform A/.

Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. 01G and (11' are sea μ planes, aη and
is next to the phosphoric acid supply hole, and - and ridge are the phosphoric acid supply holes, which are connected to the phosphoric acid supply seas Oη and ff. (■) is a sealing material between the oxidizing agent *;=021 and the gas separation plate (1), and C,021 is an M-forming agent. The brocade is the electrolyte matrix, the O-shape is the fuel electrode, and the shank is the sealing material between the fuel electrode I and the gas separation plate (1) 1, which is hollow and strip-shaped, and the shank is this hollow part.

Next, the operation will be explained. First, put the fuel side sealing material (15+) on the gas separation plate (I/I/plane Qo)', place the fuel electrode +141 between the sealing material - and the inside of O@, and place the fuel electrode +141 on the gas separation plate (17). At this time, the fuel electrode I should be brought into contact with the convex part of the fuel flow channel groove of the gas separation plate (1)', and at the same time, the phosphoric acid supply go7y of the gas separation plate (1)' should be
and the hollow part of the sealing material Oυ (lI should match 0
Next, the electrolyte matrix (131 is placed on top of the oxidizer electrode θ2 and the sheet material along it) are laminated, and the gas separation plate (1) is placed on top to form a unit. The above operations are repeated to assemble a stacked fuel cell consisting of multiple units as shown in Figure 2.
It must be made of a material that can withstand phosphoric acid at high temperatures and, unlike PTFE (tetrafluoroethylene polymer), can be melt-molded. Further, the sealing material at this time is made of powder molded so that its thickness is somewhat thicker than the thickness of each electrode.

Now, pressure is applied to the assembled stacked fuel cell using a pressing plate or the like in the stacking direction. The pressure at this time is preferably in the range of 1 to 5 kg/l:d, similar to when the electrolyte battery is operated.

After this, either you put the cell itself into an inert gas atmosphere, or you flow an inert gas instead of the fuel (river or air (121), either way, make the polarization into an inert gas atmosphere and then seal it. The material is thoroughly heat treated.

For both PFA and FEP, heat treatment should be carried out near their respective melting points (50°C for melting and baked clay).This is because the higher the temperature is than the melting point, the more the sealing material partially decomposes and the sealing properties cannot be achieved. This is because, if heat treated at a temperature considerably lower than the melting point, F-seaming will not proceed completely, the mechanical strength as a sealing material will be weak, and the V-ru properties will be poor.

During the heat treatment, pressure is simultaneously applied in the stacking direction, so that the y-y material, which was initially somewhat thicker than the electrode, becomes equal in thickness to the electrode. From this state, the temperature of the stacked battery is lowered to the operating temperature of the battery, and phosphoric acid is replenished from the phosphoric acid supply hole decoy. The supplied phosphoric acid reaches the electrolyte matrix α5Ilc from the fuel electrode V-~material hollow part Qllt'' oil through the phosphor supply hole and keeps the entire electrolyte in a wet state.

After the above operations, operate the stacked fuel cell and extract the output.

In the above example, the sealing material (!l) and (1~) were explained as a powder, but the melt-molded V
-μ material may also be used, and the same effect as in the above embodiment can be obtained.

Further, in the above embodiment, the shape of the sealing material of the fuel electrode and the oxidizer electrode was as shown in FIG. It has the effect of

As described above, according to the present invention, the V-A/material, which can withstand phosphoric acid under high temperature and can be melted, is placed between the cell and the gas separation plate, and is heat-treated so that the sea material is fused. Since the structure is twisted in a similar manner, it is possible to integrate the cell and the gas separation plate, and to obtain a highly reliable V-μ.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view showing the structure of a conventional fuel cell unit; Figure 2 is a perspective view of a conventional stacked fuel cell;
The figure is an exploded perspective view showing the structure of a unit according to an embodiment of the present invention. In the diagram, aFA is y-A/wood. In the diagram, the same reference numerals indicate the same or equivalent parts. Agent Makoto Kuzuno - Figure 1 Figure 2 Figure 3 Procedural amendment (voluntary ) 21 Name of the invention Sealing method for stacked fuel cells 3, Person making the amendment Representative Hitoshi Katayama Department 4, Agent 6, Detailed explanation of the invention in the specification to be amended - Column 6, Description of the contents of the amendment @Page 2, line 4, "comprise, (6) is" is corrected to "comprise, (6) is".

Claims (1)

[Claims] (1) Cells and gas separation plates? J! In a stacked fuel cell in which several cells are stacked, the above-mentioned unit cell and gas separation plate have the following characteristics:
A sealing material that can withstand and melt phosphoric acid under high temperatures is installed.
The C-V method for stacked fuel cells uses heat treatment to fuse the sealing material to the cell and gas separation plate. Claim 1 (claim 1) characterized in that either one of a tetrafluoroethylene-hexafluoropropylene copolymer and a barfluoro-kilviny-tech copolymer is used as the V-μ material. The Cμ method for stacked fuel cells described.