JPH0471167A - Solid electrolyte fuel cell - Google Patents

Abstract

PURPOSE:To make gas seal easily and certainly by sealing a flat, plate cell and a gas separator plate at the peripheral faces with a non-conductive high viscosity molten body filling a sump formed at the cell periphery or the overall periphery of a laminate. CONSTITUTION:A pair of gas separator plates 5, 6 pinching a cell 1 are made of a heat resistant metal such as Ni-Cr alloy, wherein the upper gas separator plate 6 is a half plate having only at the undersurface a space 6' for supplying gas, for ex. anode gas, while the lower gas separator plate 5 has a cathode gas and anode supply gas spaces 5', 6' on respective sides. This lower gas separator plate 5 is provided in a single piece construction with a sup 7 surrounding the peripheries of the cell 1 and half plate 6 with a certain gap reserved. This sump 7 is filled with an admixture 8 of a non-conductive high viscosity molten body such as pylex glass to serve as a seal and ceramic fiber, for ex. consisting of ZrO2, retaining this molten body, and over them a frame-shaped porous ceramic plate 9 is arranged in floating condition.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to solid electrolyte fuel cells.

(B) Prior Art High-temperature solid oxide fuel cells have been attracting attention as a third generation fuel cell following (I) acid type and molten carbonate type fuel cells, and are being developed in various fields.

Since all the constituent materials of this battery are solid, the electrolyte loss, which is a problem with the conventional batteries, is completely eliminated, and since the operating temperature is as high as 1000°C, it has the advantage of high power generation efficiency. be.

However, selecting constituent materials that are stable at high temperatures for long periods of time,
It is also true that there are many problems such as the electrode attachment method to the solid electrolyte and the gas sealing method.

In particular, in the sealing method between the flat cell and the gas separation plate, the wet seal method used in conventional batteries cannot be used, and a new gas seal configuration must be developed. As a gas seal method, it is possible to use a ceramic adhesive on the sealing surface between the cell and the gas separation plate, but if the ceramic adhesive is used to completely bond the cells, the difference in thermal expansion of each constituent material will cause the temperature to rise and the gas separation plate to seal. Distortion occurs in the bonded portion, which causes cracking of the cell electrolyte plate, and also causes gas leakage due to deterioration of adhesive properties during several thermal cycles. Furthermore, in the method of sealing the sealing surfaces of the cell and the gas separation plate with glass, the glass flows out to the outside during long-term operation, impairing the sealing performance. At the same time, this method has problems such as instability due to large changes in the height of the entire battery between assembly and operation.

(c) Problems to be Solved by the Invention The present invention solves the problems in conventional sealing methods and provides a solid electrolyte fuel cell with improved sealing performance.

(d) Means for Solving the Problems The first invention of the present invention comprises a flat cell consisting of an anode, a solid electrolyte, and a cathode, and a gas separation plate forming each gas supply space on the back of each of the anode and cathode. In a solid electrolyte fuel cell that is alternately stacked, a reservoir is formed integrally with each gas separation plate at a distance from the outer periphery of the upper adjacent gas separation plate, and each reservoir is filled with a non-conductive high-viscosity melt. and that the holding member for the molten body is fully filled.

Further, the second invention provides a solid electrolyte fuel cell in which a flat cell consisting of an anode, a solid electrolyte, and a cathode, and gas separation plates forming gas supply spaces on the backs of the anode and cathode are stacked alternately. The entire stack is housed in a bottomed box with a gap between them, and the reservoir formed by the gap is filled with a non-conductive high viscosity melt and a member for holding the melt.

Note that the holding member is made of non-conductive fibrous material, for example Zr0=
, Al! Non-conductive ceramic fibers such as O3, MgO, 5ift, SiC are preferred.

(e) Function According to the present invention, the flat cell and the gas separation plate are not sealed at their contact surfaces as in the past, but are filled with a reservoir formed around the outer periphery of the cell or the entire outer periphery of the stack. Since the circumferential surface is sealed with a conductive high-viscosity melt, gas sealing is easily and reliably performed, and since the holding member for the melt is also filled at the same time, there is no possibility of any vibration or tilting of the battery stack. Even in case 1, the movement of the molten material can be suppressed, and there is no inconvenience such as the molten material entering the battery constituent materials and deteriorating the battery characteristics.

(F) Embodiment FIG. 1 is a sectional view of a single cell for explaining the present invention in detail.

The flat cell (1) has an electrolyte layer (2) consisting of a fired body of zirconia stabilized with 8% ittria, and
An anode pole (3) made of O* cermet and LaCo
0s, a cathode electrode (4) made of a perovskite type oxide such as LaCrOs, and a cathode electrode (4) made of a perovskite type oxide such as
) (4) was prepared by adding a binder, a plasticizer, and a solvent to the electrode component powder to form a slurry, and applying this slurry to each surface of the electrolyte layer (2) to a thickness of 0.2 mm, followed by post-baking.

A pair of gas separation plates (5) (6) sandwiching this cell (1).
) is a nickel-chromium alloy (Inconel 600.601
), the upper gas separation plate (6)
For example, the anode gas supply space (6°
), the lower gas separation plate (5) has supply spaces (5°) (6') for cathode gas and anode gas on both sides, respectively. [The anode gas passage (6') is not shown in Figure 1, but the gas separation plate (5) has a reservoir spaced apart from the outer periphery of the cell (1) and the half plate (6). (7) are integrally formed. This reservoir (7) is filled with a mixture (8) of a non-conductive high viscosity melt (molten at 1000°C), such as Pyrex glass, which serves as a sealing material, and a Zr0t ceramic fiber, for example, which holds this melt. ) on which a frame-shaped non-porous ceramic plate (9) is placed in a floating state.

The role of this frame-shaped plate (9) is to reduce contamination of impurities or scattering of melt from the outside.

FIG. 2 is a longitudinal sectional view of an embodiment applied to a 4-cell stack, FIG. 3 is a longitudinal sectional view of the same and other embodiments, and FIG. 4 is a partially transparent top view of FIGS. 2 and 3. FIG. 5 is a cross-sectional view of FIGS. 2 and 3 as well. In these drawings, the corresponding parts are given the same symbols as in Fig. 1.

In the embodiment shown in Fig. 2, the melt and the holding member are integrated with all the gas separation plates (5), except for the gas separation plate (6) which has an anode gas supply space (6°) on only one side of the top. A reservoir (7) for a mixture (8) is formed. The gas separation plate (5) at the bottom also has a cathode gas supply space (
5゛).

On the other hand, in the other embodiment shown in FIG. 3, the entire four-cell stack is placed in a bottomed box (10) made of a heat-resistant metal such as a nickel-chromium alloy, which is the same material as the gas separation plate. A single reservoir (7°) configured by the spacing
is filled with a mixture (8°) of a non-conductive high viscosity melt and a holding member. This box body (10) has a cathode gas space (5°) on the inner bottom surface and also serves as a half plate.

2 and 3 are both cross-sectional views along the cathode gas supply space of the internal manifold.

In addition, on the lower surface of each gas separation plate (5) and (6), a pair of grooves (
11) and (12) are formed to form a seal portion.

When assembling the ta, Pyrex glass plates held by 1rCh fibers were embedded in the reservoirs (7, 7, ) and grooves (11, 12) as sealing materials, heated to soften them, and sealed.

The Pyrex glass body held by ZrOt fibers (length 550-200p, diameter 5-
10! Im) and Pyrex glass powder were stirred and mixed in a ball mill using water as a solvent, and after drying, lot"l~2
Press molding was performed at a pressure of 0.00 kg/cm'. Thereafter, it was fired in air at 1050'C for 10 to 20 hours to make it dense, and the surface was polished before use.

FIG. 6 shows a 4-cell stack (effective area 100
cm") (solid line). For comparison, the broken line shows the life characteristics when the reservoir and groove are filled only with non-conductive high viscosity melt without using a holding member.Measurement conditions Using H! as the fuel gas and air as the oxidant gas, the current density was 300m, A/cm', and the voltage was the value per single cell.From Figure 6, the fuel cell of the present invention was operated for 1000 hours. It can also be seen that it has excellent thermal shock resistance and is stable.

In this example, Pyrex was used as an example of a non-conductive high-viscosity melt, but other materials such as S+Ot-, AItOx--IgO, etc. that do not use alkali metals, or other materials other than glass may also be used. Any non-conductive melt having a viscosity of 10"-101 poise at 1000 DEG C. (the pond operating temperature) can be similarly used.

Furthermore, the ceramic fiber used as the holding member is also made of Zr.
Not limited to O+, AItos, ~Ig0.5102, Si
A non-conductive member such as C or the like can be used similarly.

(G) Effects of the Invention As described above, according to the present invention, the flat cell and the gas separation plate are not sealed at their contact surfaces as in the past, but
The peripheral surface is sealed by a non-conductive high viscosity melt that fills the reservoir formed around the cell or the entire stack.
Gas sealing is performed easily and reliably, and the molten material alleviates the difference in thermal expansion of battery constituent materials, resulting in a seal with excellent thermal shock resistance.At the same time, the molten material is also filled with the holding member. Even if there is a slight vibration or tilt in the battery tank, the movement of the molten material can be suppressed, and there is no inconvenience such as the molten material entering the battery filtration material and deteriorating the battery characteristics, and it can be used for a long time. It enables stable battery operation over a long period of time, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a single cell of the solid electrolyte fuel cell of the present invention, FIG. 2 is a vertical cross-sectional view of an embodiment applied to a 4-cell stack, FIG. 3 is a vertical cross-sectional view of the same and other embodiments, and FIG. The figure is a partially transparent top view of Figures 2 and 3, Figure 5 is also Figure 2,
FIG. 3 is a cross-sectional view, and FIG. 6 is a cell characteristic diagram of the solid electrolyte fuel cell of the present invention. (1)...Cell, (3)(6)...Gas separation plate, (5゛)...Cathode gas supply space, (6')
... Anode gas supply space, (7) (7o) ... Reservoir, (8) (8°) ... Mixture of non-conductive high viscosity melt and holding member, (9) ...・Non-porous ceramic plate,
(If)) Bottomed box, groove. Figure 1

Claims (3)

[Claims] (1) A flat cell consisting of an anode, a solid electrolyte, and a cathode, and gas separation plates constituting gas supply spaces on the back surfaces of the anode and cathode are stacked alternately, and are integrated with each of the gas separation plates. A solid electrolyte, characterized in that a reservoir is formed at a distance from the outer periphery of an upper adjacent gas separation plate, and each reservoir is filled with a non-conductive high viscosity melt and a member for holding the melt. Fuel cell. (2) A flat cell consisting of an anode, a solid electrolyte, and a cathode, and a gas separation plate constituting each gas supply space on the back of each of the anodes and cathodes are stacked alternately, and the entire stack is closed-ended. 1. A solid electrolyte fuel cell, characterized in that the fuel cell is housed in a box with a gap therebetween, and a reservoir formed by the gap is filled with a non-conductive high-viscosity melt and a member for holding the melt. (3) The solid electrolyte fuel cell according to claim 1 or 2, wherein the holding member is a non-conductive fibrous body.