JPH06188010A - Separator for flat plate-shaped solid electrolyte type fuel battery and flat plate-shaped solid electrolyte type fuel battery using this - Google Patents

Abstract

PURPOSE:To provide a separator for flat plate-shaped solid electrolyte fuel type battery that can decrease pressure loss of an oxidant gas, and reduce dispersion in temperature distribution. CONSTITUTION:The entire shape of a separator is rectangular, and a long fuel gas channel is provided on the upper surface in the longitudinal direction, while a short oxidant gas channel is provided on the under surface in the direction of shorter side. The depth of the oxidant gas channel of the separator is preferably shallow in the side facing to the inlet side of fuel gas, while becoming gradually deeper toward the side facing to the outlet side of fuel gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat plate solid electrolyte fuel cell separator which can reduce pressure loss of an oxidant gas and can reduce variations in temperature distribution, and a flat plate solid electrolyte fuel cell using the same. It is about.

[0002]

2. Description of the Related Art As a flat-plate separator in a solid oxide fuel cell having an integrated multi-stage cell structure, most of the flat plate separators having a square structure have been proposed and tested according to the structure of the battery.

However, this square separator has a problem in terms of pressure loss of the oxidant gas and variation in temperature distribution.

[0004]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of such conventional separators, can reduce the pressure loss of the oxidant gas, and can reduce the variation in temperature distribution. The present invention has been made for the purpose of providing the separator and the plate-shaped solid oxide fuel cell using the separator.

[0005]

Means for Solving the Problems The present inventors have conducted various studies to develop a separator having the above-mentioned preferable characteristics, and as a result, the separator has a rectangular overall shape,
It was found that the objective can be achieved by providing a long fuel gas flow path in the long side direction on one side and a short oxidant gas flow path in the short side direction on the other side. The invention was completed.

That is, the present invention has a rectangular shape,
Further, the present invention provides a separator for a solid oxide fuel cell, in which a long fuel gas passage in the long side direction and a short oxidant gas passage in the short side direction are provided on the upper and lower surfaces, respectively.

In the separator of the present invention, the upper surface has a long fuel gas flow path along the long side, that is, the long side direction, and the lower surface has a short oxidant gas flow path along the short side, that is, the short side direction. For example, each of them is formed in a groove shape to form the gas passages on the cathode side and the anode side of the adjacent cells. Particularly preferably, the depth of the oxidant gas flow path is shallow on the side corresponding to the inlet side of the fuel gas, and gradually deeper toward the side corresponding to the outlet side of the fuel gas. preferable. Each gas flow path is not particularly limited as long as it can supply the fuel gas and the oxidant gas, and the shape and the arrangement can be appropriately selected, but it is easy to arrange the gas passages at right angles to each other. The material of the separator is usually metal or conductive ceramics such as LaCrO ₃ .

The present invention also includes a flat plate solid oxide fuel cell using the separator of the present invention.

That is, the flat plate solid oxide fuel cell of the present invention comprises the above-described rectangular separator of the present invention, and a cathode and an upper terminal respectively having a rectangular shape of approximately the same size as the separator. It comprises a flat solid electrolyte having an anode formed thereon, and these are integrated.

As described above, in the multi-stage series type battery composed of a large number of cells, a three-layer structure plate formed by forming a cathode and an anode on the upper and lower surfaces of a predetermined flat solid electrolyte plate in each cell is a predetermined separator. It is fabricated by stacking via the, the number of laminated unit cells is adjusted appropriately, and external terminals are provided at both ends.

The solid electrolyte plate is not particularly limited as long as it has oxygen conductivity. For example, yttria-stabilized zirconia (YSZ) and calcia-stabilized zirconia (CSZ).
It is composed of a plate-like material made of a known solid electrolyte such as partially stabilized zirconia or stabilized zirconia, and its thickness is usually about 0.05 to 0.3 mm, preferably 0.08 mm.
Approximately 0.25 mm is suitable. This thickness is 0.05
If it is thinner than mm, the strength is lowered, and if it exceeds 0.3 mm, the current path becomes too long, which is not preferable.

Since the cathode is on the side of an oxidant gas passage such as oxygen or air, a conductive material having corrosion resistance to the oxidant gas at high temperature, for example, La _x Sr _1-x MnO ₃ is used, and the gas permeability is improved. It is common to form a porous coating so that

Since the anode is on the side of a fuel gas passage such as hydrogen, a conductive material having corrosion resistance to the fuel gas at high temperature, such as Ni / ZrO ₂ cermet, is used and is covered porous so as to be gas permeable. It is common to form.

As a method for forming the coating of the cathode and the anode, for example, a method of applying a predetermined powder to the solid electrolyte plate by a brush coating method or a screen printing method is used. In addition, a vapor deposition method such as a CVD method, a plasma CVD method, a sputtering method, a thermal spraying method, a plasma thermal spraying method, a vacuum vapor deposition method or an electron beam vapor deposition method is also used.

Further, if the cathode and the anode can be made into a porous plate, they can be used by adhering and integrating them with a solid electrolyte.

When a solid electrolyte plate integrally formed with each electrode, a separator, and external terminals are integrated and assembled, electrodes or cathodes provided on the upper and lower surfaces of the solid electrolyte plate,
It is necessary to seal the anode and the separator or the external terminal so that gas does not leak (gas leak). For this purpose, it may be sealed with a glass paste having a softening point of about 800 ° C. This glass paste moderately softens at the operating temperature of the battery (900 to 1000 ° C.) and seals the gas. This glass is selected to have resistance to hydrogen reduction at the operating temperature of the battery, oxidation resistance to air, and steam resistance.

In order to supply the fuel gas and the oxidant gas to the cell thus assembled, the fuel gas inlet, outlet,
A manifold may be attached to the inlet and outlet surfaces of the oxidant gas.

FIG. 1 is an expanded view of the assembly mode of three-stage series cells. In each cell, a flat solid electrolyte plate 11 has a cathode 12 and an anode 13 formed on the upper and lower surfaces, respectively.

As shown in FIGS. 1 and 2, the solid electrolyte plate with the electrodes integrally formed on the upper and lower surfaces thereof is provided with grooves 14 as fuel gas flow passages in the long side direction on the upper and lower surfaces, respectively.
a, grooves 14b serving as oxidant gas flow paths in the short side direction are integrated through rectangular separators 14 provided at right angles to each other, and external terminals are provided at both ends. Groove 14b as a flow path for the oxidant gas in the separator 14
Is formed so that the side corresponding to the fuel gas inlet side is shallow and the side corresponding to the fuel gas outlet side is deep so that a constant gradient is formed in the depth.

When assembling this collective cell, it is sealed with glass paste so as not to leak gas.

FIG. 3 shows an example of attachment of the assembled battery body to the manifold. The battery main body 21 is inserted into the pipe of the tubular manifold 22, and is arranged so that the outlets of the grooves 14a and 14b face the pipe wall. The connection points (four points) between the battery body 21 and the manifold 22 are gas-sealed, and the grooves 14a,
Four gas passages 23 to 26 formed by the tubular wall of the manifold 22 and the battery body 21 at both ends of 14b.
Correspond to.

[0022]

Example A solid oxide fuel cell of three-stage series cell was produced according to the assembly mode of FIG. As the solid electrolyte plate 11, a 70 × 35 × 0.2 mm plate-shaped material made of partially stabilized zirconia which is zirconia added with 3 mol% of yttria was used. Further, the separator 14 has a size of 70 × 35 × 5 mm made of a nickel-based alloy and has a groove depth of 1.0 mm as a fuel gas flow channel and a groove depth of 1.0 to as an oxidant gas flow channel. A 3.0 mm plate was used. And
La _0.9 S _r0.1 MnO ₃ powder (average particle size of about 5 μm) was applied on the oxygen passage side to a thickness of 0.3 mm to form a cathode 1.
2. Ni / ZrO ₂ (9/1 weight ratio) on the hydrogen passage side
The cermet mixed powder of was applied to a thickness of 0.3 mm to form an anode 13.

As shown in FIG. 1, the solid electrolyte plate 11 in which each electrode is integrally formed and the rectangular separator 14 are integrated, and the softening point between the solid electrolyte plate 11 and the separator 14 is about 800.degree. A glass paste was applied for gas sealing. This glass paste softens moderately at the operating temperature of the battery and seals the gas.

The alumina manifold 22 shown in FIG. 3 was attached to the battery thus integrated. Manifold 2
A glass paste was applied to the contact portion between 2 and the battery main body 21 to seal the gas. A platinum lead wire was welded to the electrical outlet to electrically connect it.

The solid oxide fuel cell thus produced was heated. 1 ℃ / min from room temperature to 150 ℃
The temperature was raised with to evaporate the solvent of the glass paste and the solvent of the coating electrode. The temperature was raised from 150 ° C to 350 ° C at 5 ° C / min. At 350 ° C or higher, nitrogen gas is flowed to prevent hydrogen oxidation on the hydrogen passage side at 1 ° C at 5 ° C / min.
The temperature was raised to 000 ° C. Then, the temperature was maintained at 1000 ° C., hydrogen was flown to the anode side and oxygen was flown to the cathode side to start power generation. The open circuit voltage was 3.8 V and the gas cross leak was 0.3% or less of hydrogen. The discharge characteristics are shown in Table 1.

[Table 1]

When the in-plane temperature distribution of each stage of this cell was measured, it was as small as within 10 ° C. The pressure loss on the oxidant gas side was about 70% as compared with the conventional cell described below.

On the other hand, in the conventional cells shown in FIGS. 4 and 5, the discharge characteristics shown in Table 2 were obtained with the same electrode area, but the in-plane temperature distribution of each step was as large as about 30.degree. It was

[Table 2]

[0028]

In the solid oxide fuel cell separator of the present invention, since the fuel gas passage is long and the oxidant gas passage is short, the pressure loss of the oxidant gas can be reduced and the width of the temperature distribution can be reduced. Further, regarding the depth of the oxidant gas passage, the side corresponding to the inlet side of the fuel gas is made shallow, and then gradually becomes deeper as it goes to the side corresponding to the outlet side of the fuel gas. The cooling efficiency in the vicinity can be increased, and the width of the temperature distribution can be reduced.

Therefore, in the solid oxide fuel cell incorporating the separator of the present invention, the deterioration of the member due to the temperature rise due to the heat generation due to the power generation is suppressed, and the stable cell performance can be obtained. Further, the pressure difference between the fuel gas side and the oxidant gas side can be reduced, and a stable sealed state can be maintained.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view of an example of a solid oxide fuel cell main body of a three-stage series cell using a separator of the present invention.

FIG. 2 is an explanatory diagram of a separator of the present invention.

FIG. 3 is an explanatory view of a fuel cell that is a completed product by accommodating the cell body of FIG. 1 in a manifold.

[Explanation of symbols]

 11 Solid Electrolyte Plate 12 Cathode 13 Anode 14 Separator 14a, 14b Groove 21 Battery Main Body 22 Manifold

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[Procedure amendment]

[Submission date] December 2, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a perspective explanatory view of an example of a solid oxide fuel cell main body of a three-stage series cell using a separator of the present invention.

FIG. 2 is an explanatory diagram of a separator of the present invention.

FIG. 3 is an explanatory view of a fuel cell that is a completed product by accommodating the cell body of FIG. 1 in a manifold.

FIG. 4 is a schematic view of an example of a solid oxide fuel cell main body of a three-stage series cell using a conventional separator.

FIG. 5 is a schematic view of a fuel cell that is a finished product by housing the cell body of FIG. 4 in a manifold.

[Explanation of Codes] 11 Solid Electrolyte Plate 12 Cathode 13 Anode 14 Separator 14a, 14b Groove 21 Battery Main Body 22 Manifold

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Yoshida 1-3-1 Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Tonen Research Institute

Claims (3)

[Claims] 1. A separator for a solid oxide fuel cell, which has a rectangular shape and is provided with a long fuel gas passage in the long side direction and a short oxidant gas passage in the short side direction on the upper and lower surfaces, respectively. 2. The depth of the oxidant gas flow channel is shallower on the side corresponding to the fuel gas inlet side, and is gradually deeper toward the side corresponding to the fuel gas outlet side. The described separator. 3. The separator according to claim 1 or 2, and a flat solid electrolyte in which a cathode and an anode are formed on an external terminal and an upper surface and a lower surface, respectively, each having a rectangular shape having substantially the same size as the separator. A flat plate solid oxide fuel cell which is formed by integrating these.