JPS58155670A - Molten-salt fuel cell - Google Patents

Abstract

PURPOSE:To prevent reaction gas from leaking through the peripheral part of a molten-salt fuel cell by providing an airtightness-retaining member on the peripheral part of the separator. CONSTITUTION:After a groove 6 is provided on the peripheral part of a separator 3, the groove 6 is preferably provided with a sealing member so as to increase the airtightness. Or else, after minute concaves and convexes 7 are provided on the peripheral part of the separator 3, the irregular surface is preferably provided with a sealing member. The minutely irregular surface can be formed on the peripheral part of the separator 3 by sandblasting or something silimar, so that the close contact between the separator 3 and the sealing member or between the separator 3 and an electrolyte body is enhanced. As the sealing member, a heat-proof material which has either an elasticity or a plasticity is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molten salt fuel cell, and particularly to a fuel cell having a structure suitable for preventing leakage of reactant gas from the periphery of the cell.

Conventionally, as shown in FIG. 1, a molten salt fuel cell has a pair of gas-diffusing porous electrodes 2, namely an anode and a cathode, an electrolyte body 1 disposed between the two electrodes, and a gas chamber 4 for supplying a reactive gas to both electrodes. A separator 3 with a current collector 5 is also configured. The reactant gas is sealed at the contact surface between the molten electrolyte and the separator. However, if the reactor is operated continuously for a long time, the adhesion between the electrolyte body and the reactor becomes poor, resulting in leakage of the reactant gas, and the operation has to be stopped.

An object of the present invention is to provide a molten salt fuel cell suitable for preventing leakage of reactant gas from the periphery of the cell, which is a problem in the prior art.

The key point of the present invention is that an airtight member is provided around the separator to prevent leakage of the reaction gas.

Specifically, the present invention is achieved as follows. (1
) A groove is provided in the periphery of the separator, and preferably a sealing material is provided in the groove to improve airtightness. (2)
Fine irregularities are provided on the periphery of the separator, and preferably a sealing material is provided on the irregular surface.

The peripheral area of the separator can be processed with fine irregularities using sand plaster or the like, thereby improving the adhesion between the separator, the sealing material, and the electrolyte body. (3) Protrusions are provided around the separator to improve gas sealing by utilizing the protrusions biting into the electrolyte body.

The sealing material used in the present invention is preferably a heat-resistant material having elasticity or plasticity. For example, a mixture of a eutectic mixture that has a eutectic point below the battery operating temperature and a matrix material to hold it is placed in grooves or uneven surfaces around the separator, and then heated to a temperature above the eutectic point. to form a clay-like substance to seal out the reaction gas. The eutectic mixture is not particularly limited, but for example, lithium carbonate and potassium carbonate, potassium heptadide and aluminum fluoride, etc. can be used. 9 A substance that is stable around the battery operating temperature of 650 C is preferred. The matrix material is preferably a substance that is stable with the eutectic mixture, or a substance that reacts with the eutectic mixture to produce a stable substance.

Generally, fine ceramic powder is preferred.

The present invention will now be described in more detail with reference to Examples.

Example 1 An embodiment of the present invention will be explained with reference to FIG.

A groove 6 with a depth of 1.5 wm and a width of 5 m is installed around the separator.
A mixture of lithium carbonate and potassium carbonate (1:1) and lithium aluminate powder (average particle size 0.5 μm
) 50% by weight was added and thoroughly mixed for filling. Using this separator, a nickel electrode and an electrolyte plate were combined to construct a battery as shown in FIG. Place the battery in an alumina container, set it in an electric furnace, and apply 50% H to the anode! -N, gas, 25% 0. on cathode. -25% CO! A power generation test and a gas leakage test were conducted at 650C through the reaction source 1 while passing Nt gas through the reactor. For the gas leak test, a gas sampling tube is placed in an alumina container, a sample gas is taken, and H is analyzed using gas chromatography.
l was measured. The experimental results are shown in Table 1.

Example 2 An embodiment of the present invention will be explained with reference to FIG.

A fine uneven surface 7 having a width of 5 m was formed on the periphery of the separator using sand plaster. On the uneven surface, fine alumina powder (average particle size 0.38μ) was added to a mixture of potassium fluoride and aluminum fluoride (1:1), and a small amount of ethyl alcohol was added, kneaded to form a clay, and strongly mixed with a spa chiller. I painted it.

Using this separator, a cell was assembled in the same manner as in Example 1, and a power generation test and a gas leakage test were conducted. Table 1 shows the results of the sojourn.

Example 3 An embodiment of the present invention will be explained with reference to FIG.

A C protrusion 8f: 0.5 cm in height and 1.0 cm in width is provided on the periphery of the separator to form a single cell as shown in Fig. 6.
A power generation test and a gas leak test were conducted in the same manner as above. The experimental results are shown in Table 1.

[I) According to the present invention, the reactant gas is effectively sealed, and 1. It is possible to operate continuously for a long period of time safely, and 1. It is also possible to increase the size and stack the batteries.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the configuration of a conventional fuel cell, Fig. #I2 is a plan view of a separator with a # attached to its periphery in an embodiment of the present invention, and Fig. 3 is a separator with grooves attached to its periphery. FIG. 4 is a plan view of a separator in which a finely uneven surface is provided on the periphery according to another embodiment of the present invention; FIG.
FIG. 5 is a plan view of a separator provided with protrusions on the periphery according to another embodiment of the present invention, and FIG. 6 is a sectional view showing the structure of a battery having a separator provided with protrusions on the periphery.

Claims (1)

[Claims] 1. A device comprising a pair of spaced apart gas-diffusion porous electrodes, an electrolyte body installed between the electrodes, a gas chamber and a current collector for supplying a reaction gas to both the electrodes. What is claimed is: 1. A molten salt fuel cell comprising: a separator; an airtight member is disposed around the entire circumference of a part of the contact surface of the separator with the electrolyte body; 2. The molten salt fuel cell according to claim 1, wherein the airtight maintaining member comprises a recess provided around the separator and a sealing material filled in the recess. λ Claims #! 2. The molten salt fuel cell according to claim 1, wherein a protrusion is provided at a peripheral portion of the electrolyte side surface of the separator, and the protrusion is embedded in the electrolyte body.