JPH05258759A - Solid electrolyte type fuel battery - Google Patents

Abstract

PURPOSE:To cause a reaction gas to uniformly flow in gas flow slits of a substrate. CONSTITUTION:A solid electrolyte type fuel cell comprises a substrate prepared by forming slits in a central part of each side wall 24 and inserting into these slits ceramic thin plates such as anti-reducing/heat-resisting alumina or YSZ or metallic thin plates, the thin plates being positionally adjusted after they are inserted, by which the end portions of the thin plates are made equal to or lower than the upper end of the side wall 24, and gas nontransmission layers 25 inserted into the side walls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supporting membrane type solid oxide fuel cell, and more particularly to a side wall forming a gas flow groove of a substrate.

[0002]

2. Description of the Related Art A solid oxide fuel cell is a fuel cell represented by yttria-stabilized zirconia (hereinafter referred to as YSZ) which uses a solid electrolyte having ionic conductivity at high temperature as an electrolyte. It has features such as high efficiency and high power density, and since the electrolyte is solid, consideration is given to evaporation and outflow of the electrolyte, and differential pressure control of the reaction gas, like phosphoric acid type and molten carbonate type fuel cells Since it can be reduced, it is a fuel cell with high expectations.

However, since the specific resistance of YSZ itself is high, the internal resistance of the battery cannot be increased from the viewpoint of battery performance, and the maximum thickness of YSZ is about 0.3 mm. FIG. 3 is an exploded perspective view showing a conventional self-supporting membrane type solid oxide fuel cell. A single cell is formed by stacking two electrodes, a fuel electrode 12 and an air electrode 13, on both surfaces of a self-supporting thin electrolyte plate 11. The unit cells are alternately laminated with the separator.
However, since the electrolyte plate of this type of battery is extremely brittle, it is difficult to form a large-area cell, and even if it is possible, it is difficult to handle, and it is difficult to increase the size of the battery. Therefore, in order to form this thin film of YSZ, a porous substrate is first manufactured, and a solid electrolyte body is formed on the porous substrate by a plasma spraying method,
A supporting film method of stacking by a slurry coating method or the like has been proposed.

FIG. 4 is an exploded perspective view showing a conventional support membrane type solid oxide fuel cell. A solid electrolyte body 15 made of a thin film of YSZ is formed on a thick substrate 14 made of Ni-YSZ, and a cathode 16 made of lanthanum manganite La (Sr) MnO ₃ is further laminated on the solid electrolyte body 15 to form a unit cell assembly. Is formed. Further, a dense lanthanum chromite LaCrO ₃ 17 is laminated on a substrate 18 made of lanthanum manganite LaMnO ₃ to form a separator.

Since the solid oxide fuel cell is operated at a high temperature of about 1000 ° C., the thermal strain generated in the cell material is generally large. For this reason, as the support membrane type solid oxide fuel cell, an internal manifold type in which a manifold for supplying the fuel gas and the oxidant gas is provided in the center of the substrate has been proposed. FIG. 5 is a plan view showing a substrate according to a conventional internal manifold system. The air supply manifold 19 and the fuel gas supply manifold 20 penetrate the substrate, and a gas flow groove 21 is formed from the fuel gas supply manifold 20 toward the peripheral portion of the substrate via the side wall 22. The fuel gas flows symmetrically from the central portion of the substrate to the peripheral portion through the gas flow groove 21.

FIG. 6 shows a different substrate according to the conventional internal manifold system, FIG. 6 (a) is a plan view, and FIG. 6 (b) is FIG.
It is an AA arrow sectional drawing of (a). Air flows spirally from the air supply manifold toward the periphery.

[0007]

However, in such a conventional internal manifold type substrate, since the substrate is porous, the reaction gas diffuses inside the side wall and flows to the adjacent gas passage groove. As a result, the reaction gas does not always flow evenly through the gas flow groove, and the distribution of the reaction gas in the substrate is not uniform, resulting in poor battery characteristics as a whole and a low reaction gas utilization rate. .

FIG. 7 is a sectional view showing the flow of a reaction gas in a conventional substrate. The present invention has been made in view of the above points, and an object thereof is to provide a solid oxide fuel cell having excellent characteristics by allowing a reaction gas to uniformly flow in a gas flow groove of a substrate.

[0009]

According to the present invention, the above object is to provide a unit cell assembly in which an electrode and a solid electrolyte body are laminated on a first substrate and a lanthanum chromite layer on a second substrate. The unitary cell assembly and the separators are alternately laminated, and the first substrate has an oxidant gas supply manifold and a fuel gas manifold that penetrate the central portion of the main surface in the thickness direction. And a gas passage groove through which the reaction gas flows from one of the two manifolds toward the peripheral portion of the substrate, and a gas impermeable layer is provided on the side wall forming the gas passage groove. The second substrate has an oxidant gas manifold and a fuel gas manifold that penetrate through the central portion of the main surface in the thickness direction, and reacts from the other manifold with respect to the one manifold toward the peripheral portion of the substrate. It is accomplished by a comprises a gas channel part of the flow of the scan.

[0010]

The gas impermeable layer provided on the side wall limits the amount of reaction gas that diffuses inside the substrate and flows into the adjacent gas flow groove.

[0011]

【Example】

Example 1 FIG. 1 is a sectional view showing a substrate of a solid oxide fuel cell according to an example of the present invention. NiO on the outer peripheral side surface of the side wall 24
-A suspension of YSZ is applied. This NiO-YSZ suspension was prepared by dissolving polyvinyl butyral (PVB) in isopropyl alcohol and toluene as a solvent and adding N
This is a liquid in which iO-YSZ fine powder is suspended. Atmosphere 15
By firing at 00 ° C., the gas impermeable layer 25 is formed.

Instead of the NiO-YSZ suspension, a YSZ suspension dispersed in ethanol may be applied and baked at 1450 ° C. The application and firing of these suspensions are repeated several times as necessary. Example 2 FIG. 2 is a sectional view showing a substrate of a solid oxide fuel cell according to another example of the present invention. In this embodiment, the gas impermeable layer 25 is inserted inside the side wall 24. Such a substrate is prepared by forming a slit in the central portion of the side wall 24 and inserting a reduction-resistant and heat-resistant alumina, a ceramic thin plate such as YSZ, or a metal thin plate into the slit. At this time, the edge of the thin plate is equal to or lower than the upper end of the side wall.

[0013]

According to the present invention, it has a unit cell assembly in which an electrode and a solid electrolyte body are laminated on a first substrate, and a separator in which lanthanum chromite is laminated on a second substrate, The battery cell assembly and the separator are alternately stacked,
The first substrate has an oxidant gas supply manifold and a fuel gas manifold penetrating the central portion of the main surface in the thickness direction, and from one of the two manifolds toward the peripheral portion of the substrate. The second substrate is provided with a gas flow groove through which the reaction gas flows, and a gas impermeable layer is provided on the side wall forming the gas flow groove, and the second substrate has an oxidizer penetrating the center of the main surface in the thickness direction. A gas manifold and a fuel gas manifold are provided, and since the reaction gas flows from the other manifold to the one manifold toward the peripheral portion of the substrate, the reaction gas flows inside the substrate by the gas impermeable layer. The reaction gas is prevented from diffusing and flowing into the adjacent gas flow groove, and as a result, the reaction gas uniformly flows through the gas flow groove, and the reaction gas is evenly distributed to the electrodes.
A solid oxide fuel cell having improved cell characteristics and reaction gas utilization rate can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a substrate of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a substrate of a solid oxide fuel cell according to another embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a conventional self-supporting membrane type solid oxide fuel cell.

FIG. 4 is an exploded perspective view showing a conventional support membrane type solid oxide fuel cell.

FIG. 5 is a plan view showing a substrate according to a conventional internal manifold system.

6A and 6B show different substrates according to a conventional internal manifold system, FIG. 6A is a plan view, and FIG. 6B is AA of FIG. 6A.
Sectional view

FIG. 7 is a sectional view showing a flow of a reaction gas in a conventional substrate.

[Explanation of symbols]

 23 Gas Flow Groove 24 Side Wall 25 Gas Impermeable Layer 15 Solid Electrolyte

Claims (5)

[Claims] 1. A single cell combined body having an electrode and a solid electrolyte body laminated on a first substrate, and a lanthanum chromite laminated separator on a second substrate. And the first substrate has an oxidant gas supply manifold and a fuel gas manifold that penetrate through the central portion of the main surface in the thickness direction, and the first substrate is connected to either one of the two manifolds. The substrate is provided with a gas flow groove through which the reaction gas flows toward the peripheral portion of the substrate, and a gas impermeable layer is provided on the side wall forming the gas flow groove. The second substrate has a thick central portion of the main surface. Characterized by having an oxidant gas manifold and a fuel gas manifold penetrating in the vertical direction, and having a gas flow groove through which a reaction gas flows from the other manifold to the one manifold toward the peripheral portion of the substrate. Solid electrolyte type fuel cell. 2. The solid oxide fuel cell according to claim 1, wherein the gas impermeable layer is provided on the side wall surface. 3. The solid oxide fuel cell according to claim 1, wherein the gas impermeable layer is inserted inside the side wall. 4. The solid oxide fuel cell according to claim 1, wherein the first substrate is a nickel-yttria-stabilized zirconia Ni-YSZ substrate and the second substrate is lanthanum manganite LaMnO _3. Solid oxide fuel cell. 5. The solid oxide fuel cell according to claim 1, wherein the gas impermeable layer is nickel-zirconia Ni-Zr.
A solid oxide fuel cell, which is O ₂ , yttria-stabilized zirconia, or alumina.