JPH0668975B2 - Solid electrolyte tube for sodium-sulfur battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a solid electrolyte tube for a sodium-sulfur battery, and more particularly, to improve the mechanical strength of the solid electrolyte tube to improve battery assembly and battery operation. The present invention relates to a structure of a solid electrolyte tube capable of improving durability reliability during temperature rising / falling and reducing ion conduction resistance to improve battery capacity.

(Prior Art) Recently, research and development of a high temperature type sodium-sulfur battery which is excellent in both performance and economy as a secondary battery for electric vehicles and for storing electric power at night and which operates at 300 to 350 ° C. ing.

As this sodium-sulfur battery, conventionally, as shown in FIG. 7, a cylindrical anode container 1 for accommodating a conductive material M for an anode such as carbon mat impregnated with molten sulfur S as an anode active material, and the anode container 1. A cathode container 3 which is connected to the upper end of 1 through an insulating ring 2 made of α-alumina and which stores molten metal sodium Na, and which is fixed to the inner peripheral portion of the insulating ring 2 and has a cathode active material. And a solid electrolyte tube 4 made of polycrystalline β-alumina having a cylindrical shape with a bottom and having a function of selectively transmitting sodium ions (Na ⁺ ).

A slender cathode tube 5 extending through the cathode container 3 to the bottom of the solid electrolyte tube 4 is penetratingly supported at the center of the upper lid of the cathode container 3.

Then, at the time of discharge, sodium ions permeate the solid electrolyte tube 4 and react with the sulfur S in the anode container 1 by the following reaction to generate sodium polysulfide.

2Na + XS → Na ₂ Sx Also, during charging, a reaction reverse to that during discharging occurs, and sodium Na and sulfur S are produced.

The solid electrolyte tube 4 of the sodium-sulfur battery configured as described above is appropriately mixed with aluminum oxide, sodium oxide, lithium oxide, magnesium oxide or the like, rubber-press molded, and then heated in an electric furnace. Formed by sintering. Since the solid electrolyte tube 4 is used by being fitted to the insulating ring 2 and also fitted to the anode conductive material M as described above, high mechanical strength is required and the sodium ion conduction resistance is lowered. Required to do so.

(Problems to be Solved by the Invention) In the conventional solid electrolyte tube 4 having the above-mentioned single structure, the mixing ratio of lithium oxide (Li ₂ O) or magnesium oxide (MgO) as a stabilizer, the firing temperature, etc. By changing, mechanical strength and ionic conduction resistance can be adjusted. However, when the mechanical strength is increased, the ionic conduction resistance is increased, and conversely, when the ionic conduction resistance is decreased, the mechanical strength tends to be reduced, and therefore, the β-structure of the single structure tends to decrease.
It is extremely difficult for the solid electrolyte tube 4 made of alumina to satisfy both characteristics, and if there is an assembly error between the insulating ring 2 and the solid electrolyte tube 4 or a manufacturing error of the anode conductive material M, sodium-sulfur is produced. When the solid electrolyte tube 4 is fitted into the conductive material M for the anode when the battery is assembled, the solid electrolyte tube 4 is
There was a problem that the stress was concentrated on the base end of the and was destroyed. Even when the above-mentioned manufacturing error does not cause a problem, the solid electrolyte is caused by the thermal strain due to the melting and solidification of the sulfur impregnated in the anode conductive material M, the thermal strain of the anode conductive material M, or the like when the battery is heated or cooled. There was a problem that the pipe 4 was stressed and damaged. On the other hand, when the solid electrolyte tube 4 is made thicker so as not to be damaged, there is a problem that the ionic conduction resistance increases and the battery capacity decreases.

A first object of the present invention is to provide a solid electrolyte tube for a sodium-sulfur battery which can improve mechanical strength and durability durability.

A second object of the present invention is to provide a solid electrolyte tube for a sodium-sulfur battery, which can increase mechanical strength and reduce ionic conduction resistance.

Furthermore, a third object of the present invention is to provide a solid electrolyte tube for a sodium-sulfur battery which can omit the work of joining the solid electrolyte tube and the insulating ring in addition to the second object.

(Means for Solving the Problem) In order to achieve the first object, the solid electrolyte tube according to claim 1 has both inner and outer surfaces, particularly an outer surface, of a solid electrolyte tube body having a single structure made of β-alumina. Above, the means for integrally sintering the outer coat layer made of β-alumina, which has a higher shrinkage rate during firing and cooling than the main body, is adopted.

In order to achieve the second object of the solid electrolyte tube according to the second aspect, the solid electrolyte tube main body is formed of β-alumina having a smaller ionic conduction resistance than β-alumina forming the proximal end cylinder portion, and the solid electrolyte tube is formed on the insulating ring. The base tube part to be fitted is made of β-alumina, which is stronger than the β-alumina forming the body, and the solid electrolyte tube body and the base tube part are integrally sintered. is doing.

In order to achieve the second object, the solid electrolyte tube according to claim 3 is the solid electrolyte tube according to claim 2, wherein the solid electrolyte tube main body and the proximal end tube portion have intermediate physical properties therebetween. The method of integrally sintering the intermediate tubular portion made of β-alumina is adopted.

In order to achieve the third object of the solid electrolyte tube according to claim 4, the solid electrolyte tube main body is formed of β-alumina having an ion conduction resistance smaller than that of β-alumina forming the proximal end cylinder portion. The tubular portion and the insulating ring are made of α-alumina, and the solid electrolyte tube body made of β-alumina and α
-Means of integrally sintering the base end cylinder made of alumina and the insulating ring.

In order to achieve the third object, the solid electrolyte tube according to claim 5 is the solid electrolyte tube according to claim 4, wherein α-alumina is included between the solid electrolyte tube body and the proximal end tube portion. The means is to integrally sinter the intermediate cylinder part made of a substance mixed with β-alumina.

(Operation) In the solid electrolyte tube according to claim 1, since the outer coating layer having a large firing shrinkage rate is integrally adhered and sintered on the surface of the solid electrolyte tube body, the solid electrolyte tube is contracted by the outer coating layer. The tube body is compressed, and therefore the mechanical strength is improved. When the tube body is fitted and fixed to the insulating ring and used in a sodium-sulfur battery, even if stress is applied to the proximal end tube portion, it is destroyed by the stress. There is no such thing.

Also, in the solid electrolyte tube according to the second aspect, the mechanical strength of the proximal tube portion is improved. Therefore, when the solid electrolyte tube is fitted and fixed to an insulating ring and used in a sodium-sulfur battery, stress is applied to the proximal tube portion. Even if it acts, it is not destroyed by the stress. Further, since the solid electrolyte tube main body is formed of β-alumina having a lower ionic conduction resistance than the base end tube portion, the battery capacity is increased.

In addition to the function of the solid electrolyte tube according to claim 2, the solid electrolyte tube according to claim 3 suppresses a rapid composition change in the connection between the solid electrolyte tube body and the proximal end tube portion, and thus the thermal expansion of both members. The difference in the rate and the thermal strain are absorbed by the intermediate cylindrical body, and the mechanical strength is improved.

In the solid electrolyte tube according to claim 4, the base end tube portion and the insulating ring are integrally formed of α-alumina. Therefore, in addition to the function of the solid electrolyte tube according to claim 2, the insulating ring and the solid electrolyte are provided. The step of connecting the pipes separately is unnecessary.

According to the solid electrolyte tube of the fifth aspect, in addition to the function of the solid electrolyte tube of the third aspect, the step of separately connecting the insulating ring and the solid electrolyte tube body is not necessary.

(Examples) Examples 1 to 4 embody the method for producing a solid electrolyte tube according to claim 1, and Examples 5 and 6 show a method for producing a solid electrolyte tube according to claim 2 and Example 7, 8 is a method for manufacturing a solid electrolyte tube according to claim 3, Example 9 is a method for manufacturing a solid electrolyte tube according to claim 4, and Example 10 is a method for manufacturing a solid electrolyte tube according to claim 5. It is a thing. Each embodiment will be described below in order.

Example 1 First, 90.2 parts by weight of aluminum oxide (Al ₂ O ₃ ) 9.0
Specific surface area by pulverizing, mixing and calcining a mixture consisting of 1 part by weight sodium oxide (Ma ₂ O) and 0.8 parts by weight lithium oxide (Li ₂ O) by wet pulverization with a 100 ball mill.
A powder containing 5 m ² / g β-alumina is prepared.

Then, the β-alumina-containing powder is granulated with a spray dryer to a predetermined particle size (average particle size is 40 to 120 μm).

Next, using a rubber press molding machine (isostatic press machine), the pressure is 1.5 ton / cm ² and the outer diameter is 15 m, for example.
A single-body solid electrolyte tube body 4a '(see FIG. 2) having a m-shape, a wall thickness of 1.0 mm and a length of 150 mm and having a tubular shape is formed.

Further, the molded body is immersed in a slurry of β-alumina-containing powder having a specific surface area of 9 m ² / g and having the same composition as that of the solid electrolyte tube body 4a ′, and the surface of the body 4a ′ has a thickness of 0.2 mm. To form the outer coat base material 4b '(see the chain line in FIG. 2). Then, after drying, surface finishing and degreasing, 16
By firing at 10 ° C. for 5 minutes, as shown in FIG. 1, the solid electrolyte tube 4 is obtained by integrally coating the outer surface of the solid electrolyte tube body 4a with the outer coat layer 4b.

The thickness of the outer cover layer 4b is about 1/100 to 1 of the thickness of the main body 4a.
It is set to / 2.

In the solid electrolyte tube 4 thus obtained, since the specific surface area of the outer coating layer 4b is larger than that of the main body 4a, the shrinkage rate of the outer coating layer 4b during firing and cooling is larger than that of the main body 4a, Therefore, the solid electrolyte tube body 4a is compressed by the outer coat layer 4b, and the strength of the solid electrolyte tube 4 increases. The outer layer
Even if the specific surface area of 4b is increased, there is no problem because the ionic conduction resistance does not change so much as to affect the battery function.

Example 2 A formulation consisting of 89.3 parts by weight of variable aluminum, 10 parts by weight of sodium oxide and 0.7 parts by weight of lithium oxide,
Grinding, mixing, and calcination as in Example 1 to give a specific surface area of 5 m ² /
g of β-alumina-containing powder was prepared, and this was sprayed in the same manner as in Example 1 to give a predetermined particle size (average particle size: 40
Granulate to 120 μm).

Next, using a rubber press molding device, pressure 1.5ton / cm
^2, for example, an outer diameter of 15 mm, wall thickness 2.0 mm, forming a solid electrolyte tube body base material 4a of the single structure '(see FIG. 2) forming the bag tubular length 150 mm. About this solid electrolyte tube body 4a '
Degreasing at 1000 ° C. for 2 hours, and the specific surface area of the surface of the body 4a ′ after degreasing is 9 m ² having the same composition as that of the body 4a ′.
/ G of β-alumina-containing powder slurry is applied by spraying to form a 0.5 mm-thick outer layer base 4b 'on the surface of the main body 4a'. Then, after drying, surface finishing and degreasing, it is baked at 1600 ° C. for 10 minutes to integrally form the outer coating layer 4b on the outer surface of the solid electrolyte tube body 4a. To get

(Example 3) A specific surface area was obtained by crushing, mixing and calcining a formulation consisting of 89.0 parts by weight of aluminum oxide, 9.0 parts by weight of sodium oxide and 2.0 parts by weight of magnesium oxide in the same manner as in Example 1.
A powder containing β-alumina of 5 m ² / g was prepared and granulated to a predetermined particle size (average particle size of 40 to 120 μm) by a spray dryer as in Example 1.

Next, using a rubber press molding machine, pressure 2.5ton / cm
² , the outer diameter is 15 mm, the wall thickness is 2.0 mm, and the length is 150 mm.
Mold 4a '. A specific surface area of 9 m ² having the same composition as that of the base body 4a ′ with respect to the surface of the base body 4a ′ of the solid electrolyte tube.
/ G of β-alumina-containing powder slurry is applied by spraying to form a coating layer base 4b 'having a thickness of 0.2 mm. After that, after drying, surface finishing and degreasing, at 1630 ℃
The solid electrolyte tube 4 shown in FIG. 1 is obtained by firing for 30 minutes to integrally form a jacket layer 4b on the surface of the solid electrolyte tube body 4a.

(Example 4) A mixture of 87.0 parts by weight of aluminum oxide, 10 parts by weight of sodium oxide and 3.0 parts by weight of magnesium oxide was pulverized, mixed and calcined in the same manner as in Example 1 to give a specific surface area of 5 m.
^A powder containing ² / g of β-alumina is prepared and granulated to a predetermined particle size (average particle size is 40 to 120 μm) by a spray dryer.

Next, using a rubber press molding machine, pressure 2.0ton / cm
² , a solid electrolyte tube body 4a 'of a single structure shown in FIG. 2 is formed, which has a tubular shape with an outer diameter of 15 mm, a wall thickness of 1.0 mm and a length of 150 mm. This base material 4a 'was degreased at about 1000 ° C. for 2 hours, and the degreased base material 4a' was immersed in a slurry of β-alumina-containing powder having a specific surface area of 9 m ² / g and the same composition as the base material. ′ Surface 0.3 mm thick outer layer substrate 4
Deposit b '. Then, after drying, surface finishing, and degreasing, baking is performed at 1610 ° C. for 10 minutes, and the outer coating layer 4b is integrally formed on the outer surface of the solid electrolyte tube main body 4a to form the solid electrolyte tube shown in FIG. Get 4.

Example 5 A formulation consisting of 90.5 parts by weight aluminum oxide, 9 parts by weight sodium oxide and 0.5 parts by weight lithium oxide,
The β-alumina-containing powder A was pulverized, mixed and calcined in the same manner as in Example 1 to prepare a powder A containing 90.2 parts by weight of aluminum oxide, 9 parts by weight of sodium oxide and 0.8 parts by weight of sodium oxide. Similarly, the β-alumina-containing powder B is pulverized and mixed to prepare the powder B. Then, the β-
Alumina-containing powders A and B are granulated to a predetermined particle size (average particle size is 40 to 120 μm) by a spray dryer as in Example 1.

Next, 85% of the total volume of the β-alumina-containing powder B is contained in a portion other than the open end portion in the molding die of the rubber press molding apparatus, that is, in the space for molding the main body 4a of the solid electrolyte tube 4, and other portions. That is, about 15 parts of β-alumina-containing powder A is filled in the space for molding the base end tube portion 4c of the solid electrolyte tube 4 shown in FIG.
%, And a solid electrolyte tube base material having a composite composition is molded at a pressure of 2.5 ton / cm ² . Then, after drying, surface finishing and degreasing, baking is performed at 1600 ° C. for 5 minutes to obtain a solid electrolyte tube 4 shown in FIG.

The solid electrolyte tube 4 thus obtained has a base end tube portion 4c.
Since it is superior in strength to the main body 4a, it can sufficiently withstand the stress acting during battery assembly or temperature rise / fall during battery operation, while the solid electrolyte tube main body 4a has an ionic conduction resistance higher than that of the proximal end tube portion 4c. Is small, the battery capacity can be improved as compared with the case where the main body 4a is formed of alumina forming the proximal end cylinder portion 4c.

Example 6 In this Example 6, a β-alumina-containing powder C was prepared in the same manner as in Example 5 by using a formulation consisting of 89.5 parts by weight of α-alumina, 9.0 parts by weight of sodium oxide and 1.5 parts by weight of magnesium oxide. Prepared and prepared as in Example 5 with a formulation consisting of 89.0 parts by weight α-alumina, 9.0 parts by weight sodium oxide and 3.0 parts by weight magnesium oxide.
-Alumina-containing powder D is prepared. The β-alumina-containing powder C forms a proximal end tube portion 4c and D forms a solid electrolyte tube body 4a to manufacture the solid electrolyte tube 4 shown in FIG. 3. The final step temperature is 1620 ° C. Since it is the same as Example 5 except that it is fired for a minute, detailed description of the manufacturing process is omitted. The solid electrolyte tube 4 thus obtained is
It has the same effect as the solid electrolyte tube of Example 5.

Example 7 In this Example 7, in addition to the β-alumina-containing powders A and B prepared in Example 5, 90.3 parts by weight of α-alumina, 9.0 parts by weight of sodium oxide and 0.7 parts by weight of lithium oxide were used. The β-alumina-containing powder E having intermediate properties is prepared by pulverizing, mixing, and calcining the above-described formulation by the wet pulverization described above.

After that, the β-alumina-containing powders A, B, and E were respectively sprayed to a predetermined particle size (average particle size of 40 to 12).
Granulate to 0 μm).

Next, as shown in FIG. 4, about 75% of β-alumina-containing powder B was filled in a portion other than the opening in the molding die of the rubber press molding apparatus, that is, the space for molding the solid electrolyte tube main body 4a, and Almost 10% of the powder E is filled in the upper cylindrical portion 4d,
Finally, about 15% of β-alumina-containing powder A was filled in the opening, that is, the space for forming the proximal end tube portion 4c of the solid electrolyte tube 4, and the solid electrolyte tube base material of composite composition was formed at a pressure of 2.5 ton / cm ^2. To do. Then, after drying, surface finishing and degreasing, baking is performed at 1590 ° C. for 10 minutes to manufacture a solid electrolyte tube 4 as shown in FIG.

In the solid electrolyte tube 4 of Example 7, the joint strength between the main body 4a and the base end cylinder 4c is improved by the intermediate physical properties of the tubular portion 4d, and the stress due to the difference in thermal expansion coefficient is relaxed.

Example 8 In this Example 8, the composition of the β-alumina-containing powders C and D of Example 6 described above, 88.7 parts by weight of α-alumina, 9.0 parts by weight of sodium oxide and 2.3 parts by weight of magnesium oxide was used. The powder 4 as shown in FIG. 4 is used to form the main body 4a, the powder F to form the cylindrical portion 4d, and the powder C to form the cylindrical portion 4c. The solid electrolyte tube 4 having a high strength is manufactured. 1630 ° C. in this Example 8.
The difference from Example 7 is that the firing is performed for about 30 minutes, and the other manufacturing steps are the same, so detailed description will be omitted.

Example 9 A formulation consisting of 89.0 parts by weight of α-alumina, 9.0 parts by weight of sodium oxide and 3.0 parts by weight of magnesium oxide was pulverized, mixed and calcined by the wet pulverization described above to obtain β-.
Alumina-containing powder G is prepared.

On the other hand, α-alumina is similarly pulverized and mixed to prepare α-alumina powder H.

Then, the β-alumina-containing powder G and the α-alumina powder H are granulated to have a predetermined particle size (average particle size is 40 to 120 μm) by a spray dryer.

Next, a portion other than the open end portion in the molding die of the rubber press molding apparatus, that is, the main body of the solid electrolyte tube 4 shown in FIG.
Almost 85% of the volume of β-alumina-containing powder G is filled in the space for molding 4a, and α-alumina powder H is filled in the space other than that, that is, in the space for molding the base end cylindrical portion 4c of the solid electrolyte tube 4 and the insulating ring 2. The solid electrolyte tube base material of composite composition is molded at a pressure of 2.5 ton / cm ² with a filling rate of about 15%. After that, after drying, surface finishing and degreasing, baking at 1630 ° C for 60 minutes β-
A solid electrolyte tube 4 as shown in FIG. 5 is manufactured in which the base end portion and the flange portion of the solid electrolyte tube made of alumina are integrally formed of α-alumina.

In the solid electrolyte tube 4 thus obtained, in addition to the operation of the fifth embodiment, the work of connecting the insulating ring 2 and the solid electrolyte tube 4 can be omitted.

Example 10 The β-alumina-containing powder G of Example 9, the α-alumina powder H, and the alumina powder I having a mixed composition of both powders G and H.
To prepare. These powders G, H and I are granulated with a spray dryer to a particle size of 40 to 120 μm.

Next, a portion other than the open end portion in the molding die of the rubber press molding apparatus, that is, a space for molding the solid electrolyte tube body 4a shown in FIG. 6 is filled with β-alumina powder G in an amount of about 75% of the volume. After filling up with about 10% of alumina powder I having an intermediate composition, the base end cylindrical portion 4c of the solid electrolyte tube 4 and the insulating ring 2 are filled.
Almost 15% of α-alumina powder H is filled in the space for molding, and the solid electrolyte tube base material of these three kinds of composite compositions is rubber press molded. Then, after drying, surface finishing and degreasing, baking was performed at 1630 ° C. for 60 minutes to obtain a solid electrolyte tube 4 as shown in FIG.

In the solid electrolyte tube 4 thus obtained, in addition to the effect of the ninth embodiment, the connection between the main body 4a and the base end tube portion 4c becomes stronger, and the stress due to the difference in the thermal expansion coefficient of both members is relaxed. can do.

The present invention can also be embodied as follows.

In the embodiment shown in FIG. 1, an inner coating (not shown) having the same composition as that of the outer coating layer 4b is formed on the inner peripheral surface of the solid electrolyte tube 4, and each of the inner coatings shown in FIGS. In the example,
It is also possible to embody by arbitrarily changing the configuration within the scope of the claims of the present invention, such as continuously changing the composition of the boundary portion.

(Effect of the invention) As described in detail above, the solid electrolyte tube according to claim 1 is
Since the outer coat layer is sintered on the surface, the solid electrolyte tube body is compressed by the contracting force of the outer coat layer without lowering the ionic conduction resistance, thus improving the mechanical strength.
There is an effect that it is possible to suppress damage to the solid electrolyte tube at the time of assembling the battery or raising or lowering the temperature of the battery operation to improve durability reliability.

Further, in the solid electrolyte tube according to claim 2, since the proximal end tube portion of the solid electrolyte tube is superior to the main body in mechanical strength, stress of the solid electrolyte tube at the time of assembling the battery or temperature rising / falling of the battery operation. The solid electrolyte tube body is formed of β-alumina, which has a lower ionic conduction resistance than the proximal end tube portion, while preventing damage due to damage and improving the durability and reliability. There is also an effect that the battery capacity can be increased as compared with the case where the main body is formed of alumina.

In addition to the function of the solid electrolyte tube according to claim 2, the solid electrolyte tube according to claim 3 strengthens the connection between the solid electrolyte tube body and the proximal end tube portion, and further, stress is generated due to the difference in thermal expansion coefficient. There is an effect that it can be relaxed and the durability of the solid electrolyte tube can be improved.

In the solid electrolyte tube according to claim 4, the base end tube portion and the insulating ring are integrally formed of α-alumina, and the whole is integrally formed. In addition to the effect, a solid electrolyte tube having an integral structure up to the flange portion can be formed, and further, a process for separately connecting the insulating ring and the solid electrolyte tube is not required, the manufacturing can be easily performed, and the cost can be reduced.

The solid electrolyte tube according to claim 5 has the effects of the solid electrolyte tube according to claims 3 and 4.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a central portion showing a solid electrolyte tube in which one embodiment of the present invention is partially omitted, and FIG. 2 shows a solid electrolyte tube main body manufactured during the manufacturing process. 3 is a longitudinal sectional view of the central portion of the solid electrolyte tube according to claim 2, FIG. 4 is a longitudinal sectional view of the central portion of the solid electrolyte tube according to claim 3, and FIG. A central longitudinal sectional view of the solid electrolyte tube according to claim 4, FIG. 6 is a central longitudinal sectional view of the solid electrolyte tube according to claim 5, and FIG. 7 is a central longitudinal sectional view of a conventional sodium-sulfur battery. Is. 2 ... Insulating ring, 4 ... Solid electrolyte tube, 4a ... Solid electrolyte tube body, 4a '... Solid electrolyte tube body base, 4b ... Outer layer, 4b' ... Outer layer base, 4c. Base end cylinder, 4c ′ ……
Base cylinder part base material, 4d …… intermediate cylinder part, 4d ′ …… intermediate cylinder part base material.

Claims (5)

[Claims] 1. A jacket layer made of β-alumina, which has a larger shrinkage factor during firing and cooling than the main body (4a), on the outer surface of a solid electrolyte tube body (4a) having a single structure made of β-alumina. A solid electrolyte tube for a sodium-sulfur battery, wherein (4b) is integrally sintered. 2. The solid electrolyte tube body (4a) is connected to the base end cylinder part (4c).
Β-alumina, which has a smaller ionic conduction resistance than β-alumina that forms the core, forms a base end tube portion (4c) fitted to the insulating ring (2) in the main body (4a).
A solid electrolyte tube for a sodium-sulfur battery, characterized in that it is made of β-alumina having a strength higher than that of alumina, and the solid electrolyte tube body (4a) and the proximal end tube portion (4c) are integrally sintered. 3. The solid electrolyte tube according to claim 2, wherein between the solid electrolyte tube body (4a) and the proximal end tube portion (4c),
A solid electrolyte tube for a sodium-sulfur battery, which is obtained by integrally sintering an intermediate tubular portion (4d) made of β-alumina having intermediate properties of both. 4. The solid electrolyte tube body (4a) is connected to the base end cylinder (4c).
It is made of β-alumina, which has a smaller ionic conduction resistance than that of the solid electrolyte tube body (4a), and the insulating tube (2) is made of α-alumina. ) And an insulating ring (2) are integrally sintered, a solid electrolyte tube for a sodium-sulfur battery. 5. The solid electrolyte tube according to claim 4, wherein an intermediate tube portion made of a material in which α-alumina and β-alumina are mixed between the solid electrolyte tube body (4a) and the proximal end tube portion (4c). A solid electrolyte tube for a sodium-sulfur battery, characterized in that (4d) is integrally sintered.