JPH03129675A - Solid electrolyte fuel cell - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a solid oxide fuel cell, and particularly to a solid oxide fuel cell that is free from thermal damage and has excellent reliability.

[Conventional technology]

Fuel cells using oxide solid electrolytes such as zirconia are
Because its operating temperature is as high as 800-1100℃,
It has high power generation efficiency, does not require a catalyst, and is easy to handle because the electrolyte is solid, so it is expected to be used as a third-generation fuel cell.

However, solid oxide fuel cells are prone to thermal damage because their main constituent material is Cera Densoku.
Furthermore, it has been difficult to realize this because there is no appropriate gas sealing method. Therefore, a cylindrical fuel cell with a special shape was devised, which solved the above two problems and successfully completed the battery operation test. There are still no prospects for low-density, economically advantageous options.

In order to increase the power generation density, it is necessary to use a flat plate type. As a flat plate type fuel cell, for example, one having a structure shown in an exploded perspective view of FIG. 4 is known.

In this type of fuel cell, single cells 17 (consisting of a solid electrolyte plate 17A and electrodes 17B and 17C) and separate plates 18 are alternately stacked, and grooves of the separate plates that intersect at right angles in a three-dimensional manner contain different reactions. Gas is flushed.

C) Reactant gases are individually introduced into the fuel cell using a gas manifold (not shown). At this time, in order to separate and sufficiently supply the reaction gas into the fuel cell, it is necessary to perform a gas seal between the unit cell 17 and the separate plate 18. One possibility is to sinter the single cell 17 and the separate plate 18 together in order to achieve gas sealing, but in this method, the single cell and the separate plate are made of different materials, so a small coefficient of thermal expansion is required. Cracks occur in the monolithic sintered body due to differences and non-uniformity in temperature distribution.

The present invention has been made in view of the above-mentioned points, and its purpose is to provide a solid oxide fuel cell that is free from thermal damage and has excellent reliability by improving the flow of reactant gas.

[Means to solve the problem]

The above-mentioned object according to the invention includes a single cell 17.13 and a reactant gas distribution means 18.14.7.
and a manifold 4.5, the single cell is composed of an anode, a solid solute, and a cathode, and the reaction gas distribution means is stacked alternately with the single cell and has ribs 20 as guide vanes. through which the fuel gas and oxidant gas are separately distributed to the anode and cathode of the single cell, and the ribs 20 distribute the reactant gas from the central part of the reactant gas distribution means toward the reactant gas outlet 16, 19 at the peripheral part. The reactant gas discharge ports 16 and 19 are arranged in a uniform distribution around the battery consisting of the stacked reactant gas distribution means and single cells, and the manifolds 4 and 5 react with the stacked single cells. This is achieved by supplying the reactive gas to the reactive gas distribution means by penetrating the central portion of the gas distribution means.

Reactant gas distribution means include ribbed substrates and ribbed substrates on which interconnectors are laminated and supported.

These ribbed substrates may be porous or have dense chambers, as required.One reaction gas outlet is arranged in a manner to independently distribute the oxidizing gas and the fuel gas.

[Effect]

The reactant gas flows radially from the center of the cell toward the periphery, eliminating the need for a gas seal between the single cell and the reactant gas distribution means. The reaction gas burns around the battery, but the distribution of the exhaust ports is negative, so the ambient temperature is uniform.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings. 1st
The figure is a perspective view of a solid oxide fuel cell according to an embodiment of the present invention, and the oxidant gas discharge port 16 is located 9 in the circumferential direction with the discharge port 16A of the cell directly above and the discharge port 16B of the cell directly below.
They are arranged offset by 0 degrees.

Similarly, the fuel gas discharge port 19 is also the discharge port 19 of the upper and lower cells.
A and 19B are arranged 90 degrees apart in the circumferential direction.

The angle of displacement in the circumferential direction is not limited to 90 degrees.

FIG. 2 is a central sectional view of a fixed electrolyte fuel cell according to a different embodiment of the present invention, in which a ribbed porous base material 7 on which an anode 1, a fixed electrolyte 2, and a cathode 3 are formed, and an ink connector 12 are formed. The ribbed porous substrates 11 are alternately stacked, and a fuel gas introduction pipe 4 and an oxidant gas introduction pipe 5 are arranged in the center of the stack to form a single fuel cell.

Oxygen gas, which is an oxidizing gas, is introduced into the oxidizing gas chamber 9 on the ribbed porous base material 11 by the oxidizing gas introduction pipe 5 via the gas hole 10A. Hydrogen gas, which is a fuel gas, is introduced into the fuel gas chamber 8 on the ribbed porous base material 7 by the fuel gas introduction pipe 4 via the gas hole 10B. As shown in FIG. 3, the oxidant gas chamber 9 has a gas flow path formed by a guide cylinder 20 having gas outlets concentrically shifted by 90 degrees.

The oxidant gas flows from the center to the periphery and is discharged from the gas outlet 16. The fuel gas chamber 8 has a similar shape, but since the flow rate of the reactant gas is small, the gas outlets are provided at a 180 degree angle.

The fuel gas and oxidizing gas that have reached the peripheral portion are combusted, and the temperature of the fuel cell is maintained at a predetermined high temperature. It can also be used as a heat source for residual heat of reaction gas.

Such a battery is prepared as follows.

A ribbed porous substrate 7 with a thickness of 2fi is formed using NiZr0z cermet. Ni Zr0t cermet is plasma sprayed onto the flat main surface of the ribbed porous substrate 7 to form a porous anode 1 with a thickness of 100 mm.

Ittria-stabilized zirconia is plasma sprayed onto the anode 1 to form a dense solid electrolyte 2 with a thickness of 30 mm. Next is lanthanum strontium manganite La.
(Sr)Mn03 is plasma sprayed to form a porous cathode 3 with a thickness of 800 mm. On the other hand, a ribbed porous base material 11 having a thickness of 2fi is formed using La(Sr)MnOs. Lanthanum chromite LaCrO3 is plasma sprayed onto the flat main surface of this ribbed porous base material 11 to form a dense ink connector 12 with a thickness of 40 nm.

Lanthanum chromite has electronic conductivity and is not oxidized even in an oxidizing atmosphere.

Additionally, lanthanum chromite exhibits a coefficient of thermal expansion similar to that of intoria-stabilized zirconia.

Next, the ribbed porous base material 7 on which the anode 1, the solid electrolyte 2, and the cathode 3 are formed, and the rib'-formed porous base material 11 on which the ink connector 12 is formed are individually sintered. After sintering, the side faces of the ribbed porous substrates 7 and 11 facing the fuel gas introduction pipe 4 and the oxidant gas introduction pipe 5 are covered with ceramic cement 6.
Gas sealed using.

Note that the ribbed porous base material 11 using La (Sr) MnO3 does not necessarily have to be porous;
Sr) Since MnOs is reduced in a reducing atmosphere, an interconnector using LaCrOs is necessary even if it is made dense.

〔Effect of the invention〕

According to the present invention, there is provided a single cell, a reactive gas distribution means, and a manifold, the single cell is composed of an anode, a solid electrolyte, and a cathode, and the reactive gas distribution means is stacked alternately with the single cell. , the fuel gas and the oxidizing gas are separately distributed to the anode and cathode of the single cell through ribs serving as guide cylinders, and the ribs are arranged from the center of the reactive gas distribution means toward the reactive gas outlet at the periphery. The reactant gas flows radially, the reactant gas outlet is arranged in a uniform distribution around the battery including the stacked reactant gas distribution means and the single cell, and the manifold is arranged between the stacked single cells and the reactant gas distribution means. Because the reactant gas is supplied to the reactant gas distribution means through the center of the cell stack, the reactant gas flows from the center of the cell stack, which is a stack of the single cell and the reactant gas distribution means, to the periphery of the single cell. There is no need for a gas seal between the cell member and the reaction gas distribution means, and thermal damage caused by a difference in the coefficient of thermal expansion of the cell members is eliminated.

In addition, the reaction gas is combusted after being discharged around the cell stack, but because the reaction gas discharge ports are uniformly distributed, the temperature rise at the periphery of the cell stack is uniform, resulting in thermal damage to the cell due to the temperature gradient. As a result, a solid oxide fuel cell with no thermal damage and excellent reliability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a solid oxide fuel cell according to an embodiment of the invention, FIG. 2 is a central sectional view showing a solid oxide fuel cell according to a different embodiment of the invention, and FIG. FIG. 4 is a cross-sectional view showing a solid oxide fuel cell according to an embodiment of the present invention or a different embodiment of the present invention.
FIG. 1 is an exploded perspective view of a conventional solid oxide fuel cell. l near node, 2: solid electrolyte, 3: cathode, 4: fuel gas introduction pipe, 5: oxidant gas introduction pipe, 6: ceramic cement, 7: porous base material with ribs, 8: fuel gas chamber, 9
:Oxidant gas chamber, 10A dioxide gas hole, IOB F
Fuel gas hole, 11: Porous base material with lip, 12: Interconnector, 13: Single cell, 16.16A.

Claims (1)

[Claims] 1) It has a single cell, a reactive gas distribution means, and a manifold, the single cell is composed of an anode, a solid electrolyte, and a cathode, and the reactive gas distribution means is arranged alternately with the single cell. The fuel gas and the oxidant gas are individually distributed to the anode and cathode of the single cell through ribs serving as guide vanes, and the ribs are stacked on top of each other to distribute the fuel gas and the oxidant gas to the anode and cathode of the single cell through ribs serving as guide vanes, and the ribs extend from the center of the reactive gas distribution means to the reactive gas outlet at the peripheral portion. The reactant gas is flowed radially towards the reactor gas, the reactant gas outlet is arranged in a uniform distribution around the battery including the stacked reactant gas distribution means and single cells, and the manifold reacts with the stacked single cells. 1. A solid oxide fuel cell, characterized in that a reactant gas is supplied to the reactant gas distribution means by penetrating the central portion of the gas distribution means.