JP2000251929A - Negative electrode compartment structural body for sodium-sulfur battery and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a negative electrode compartment structural body for a sodium-sulfur battery which can be sealed under a normal pressure by filling sodium in the negative electrode compartment in a vacuum, and to provide a manufacturing method for it. SOLUTION: This negative electrode compartment structural body has a sodium ion conducting solid electrolyte tube 1, a negative electrode collecting part 6 having a lower part inserted in the solid electrolyte tube 1, and a negative terminal 5 to be inserted with the upper part of the negative electrode collecting tube 6. A recessed part 9 having a through-hole 5A on its bottom part and provided with a blocking body 5B to block the through-hole 5A is formed in the upper part of the negative electrode terminal 5, and the upper part of the recessed part 9 is sealed by a sealing body 10, after the negative electrode compartment is vacuumized through an opening 11 provided on a part of the negative electrode collecting tube 6 positioned in the recessed part 9 and the negative electrode compartment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative electrode compartment structure for a sodium-sulfur battery and a method for producing the same. More specifically, the present invention relates to a negative electrode compartment in a solid electrolyte tube of a sodium-sulfur battery. The present invention relates to a structure of a negative electrode chamber constituting body which can be filled under vacuum and sealed under normal pressure, and a method for producing the same.

[0002]

2. Description of the Related Art A sodium-sulfur battery in which a negative electrode chamber is formed inside a sodium ion conductive solid electrolyte tube and a positive electrode chamber is formed outside is a high temperature type battery operated at a temperature of about 300 ° C. The structure is such that a negative electrode chamber in which sodium as a negative electrode active material is housed is welded to a negative electrode lid joined to one surface of an α-alumina ring joined to an opening of the solid electrolyte tube, and the negative electrode lid. The positive electrode chamber sealed with the negative electrode terminal and containing sulfur as a positive electrode active material is sealed with a positive electrode lid joined to the other surface of the α-alumina ring and a battery case welded to the positive electrode lid. Be done.

[0003] In such a sodium-sulfur battery, a negative electrode chamber in a solid electrolyte tube is filled with sodium as a negative electrode active material under vacuum, and a sealed negative electrode chamber structure is inserted into the battery case. Is sealed by welding to the positive electrode lid joined to the other surface of the α-alumina ring.

Conventionally, as shown in FIG. 2, an α-alumina ring 2 is connected to an opening of a sodium ion conductive solid electrolyte tube 1 by glass soldering, as shown in FIG.
A negative electrode cover 3 is joined to the upper surface of the α-alumina ring 2 by heat and pressure, and a positive electrode cover 4 is joined by heat and pressure to the lower surface, respectively. The lower portion of the negative electrode current collector tube 6 is inserted into the solid electrolyte tube 1 in which the metal fibers 7 are disposed, and the negative electrode active material is inserted into the solid electrolyte tube 1 through the through hole 5A of the negative electrode terminal 5. And filled with sodium 8 under vacuum and then sealed.

[0005]

According to the above-described method for producing a negative electrode compartment structure for a sodium-sulfur battery, about 15
At a temperature of 0 ° C., sodium 8 is filled into the solid electrolyte tube 1 under vacuum through the through hole 5A, and then moved one lot at a time into the vacuum welding chamber, where it is sealed by electron beam welding or laser welding. Therefore, there has been a problem that mass production is difficult in terms of production efficiency and cost.

[0006]

According to a first aspect of the present invention, there is provided a negative electrode compartment for a sodium-sulfur battery, wherein an α-alumina ring is joined to an opening, and the inside thereof is a negative electrode compartment. An ion-conductive solid electrolyte tube, a negative electrode current collector tube having a lower portion inserted into the negative electrode chamber, a negative electrode terminal having an upper portion of the negative electrode current tube inserted, and one end joined to the upper surface of the α-alumina ring The other end comprises a negative electrode lid welded to the negative electrode terminal, the negative electrode chamber and the negative electrode chamber are hermetically sealed by the negative electrode terminal and the negative electrode lid, and vacuum holding means is provided on the negative electrode current collector tube and the negative electrode terminal. With this, when the negative electrode chamber is evacuated after filling with sodium, the vacuum in the negative electrode chamber can be maintained by vacuum holding means thereafter, so that the vacuum welding chamber Can be sealed without moving to

According to a second aspect of the present invention, in the negative electrode compartment structure for a sodium-sulfur battery, the vacuum holding means has a through hole at the bottom formed at the top of the negative electrode terminal and for closing the through hole. A recess provided with a closing body, a sealing body for closing the upper portion of the recess, and an opening provided in a part of the negative electrode current collector tube located in the negative electrode chamber, characterized in that, With this, when the operation of evacuating the negative electrode chamber is started, the closing body floats up and opens the through hole, and when the work of evacuating is completed, the closing body drops by its own weight or pressure difference and closes the through hole, With the vacuum in the negative electrode chamber maintained, the upper part of the concave portion can be sealed with a sealing body.

According to a third aspect of the present invention, there is provided a method for manufacturing a negative electrode compartment for a sodium-sulfur battery, wherein an α-alumina ring is joined to the opening, and a negative electrode lid is joined to the upper surface of the α-alumina ring. A negative electrode chamber, a sodium ion conductive solid electrolyte tube, a negative electrode current collector tube having an opening in part, and a concave portion having a through hole at the bottom and a closing body for closing the through hole. Prepare the negative electrode terminal formed in the above, while inserting the upper part of the negative electrode current collector tube into the negative electrode terminal such that the inside communicates with the through hole of the negative electrode terminal, and the lower part of the negative electrode current collector tube into the negative electrode chamber Inserting, welding the negative electrode terminal to the negative electrode lid, filling the negative electrode chamber with sodium through the through hole of the negative electrode terminal, evacuating the negative electrode chamber through the opening and the concave portion, and then sealing the negative electrode chamber. What is Thus, it is possible to obtain a method for manufacturing a negative electrode chamber component that can contribute to improvement in production efficiency and reduction in cost.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on its embodiments.

FIG. 1 is a sectional view of a negative electrode compartment structure for a sodium-sulfur battery according to an embodiment of the present invention.

The characteristics of the negative electrode compartment structure for a sodium-sulfur battery shown in FIG. 1 are as follows. An α-alumina ring 2 is joined to the opening, and a sodium ion conductive solid electrolyte tube 1 has a negative electrode compartment inside. The lower portion has a negative electrode collector tube 6 inserted into the negative electrode chamber in the solid electrolyte tube 1, the negative electrode terminal 5 having the upper portion of the negative electrode collector tube 6 inserted therein, and one end provided on the upper surface of the α-alumina ring 2. A negative electrode cover 3 welded to the negative electrode terminal 5 at the other end; the negative electrode chamber is hermetically sealed by the negative electrode terminal 5 and the negative electrode cover 3; Is provided with vacuum holding means.

The vacuum holding means includes a concave portion 9 formed at the top of the negative electrode terminal 5 and having a through hole 5A at the bottom and a closing body 5B for closing the through hole 5A.
A sealing body 10 for sealing the upper part of the recess 9 and an opening 1 provided in a part of the negative electrode current collector tube 6 located in the negative electrode chamber.
It consists of 1.

By providing such a vacuum holding means, a negative electrode compartment for a sodium-sulfur battery can be manufactured by filling sodium into the negative electrode compartment under vacuum and then filling the negative compartment through the opening 11 and the concave portion 9. When the vacuuming operation is started, the closing body 5B rises to open the through hole 5A. When the vacuuming operation is completed, the closing body 5B drops by its own weight or the pressure difference to close the through hole 5A. Thus, the upper portion of the recess 9 can be sealed by the sealing body 10 in a state where the vacuum in the negative electrode chamber is maintained.

In the embodiment described above, the through-hole 5A of the negative electrode terminal 5 has a diameter of 1.5 mm,
Uses an inner diameter of 4.2 mm.
Although the closing body 5B having an outer diameter of 4.0 mm is arranged in the above, grease for vacuum sealing may be applied between the closing body 5B and the recess 9 as needed.

The time required for filling the negative electrode chamber for a sodium-sulfur battery in the above-described manner from filling sodium under vacuum to sealing is about 1 minute, and the lot is moved to the vacuum welding chamber one lot at a time. It has been found that the process can be simplified as compared with the conventional manufacturing method.

Next, in order to confirm the effectiveness of the above-described manufacturing method, a small hole is made in the negative electrode cover 3 and a vacuum gauge for measuring the degree of vacuum is connected thereto.
As a result of IG welding, it was confirmed that the negative electrode chamber could be maintained in a vacuum.

Further, 10 pieces of the negative electrode chamber components according to the above-mentioned manufacturing method of the present invention and 10 pieces of the conventional negative electrode chamber components produced by moving each lot to the vacuum welding chamber by one lot were subjected to sodium When the presence / absence of leakage was confirmed, it was found that sodium leakage was not observed in the case of the production method of the present invention, whereas sodium leakage was observed in all cases of the conventional production method. all right.

[0018]

As described above, according to the present invention, the negative electrode chamber component can be sealed under normal pressure, and the time required for the sealing can be shortened, so that the production efficiency can be improved and the cost can be reduced. In many cases, it can be reduced, which contributes to mass production of sodium-sulfur batteries.

Further, according to the present invention, since the negative electrode chamber structure can be sealed with the pressure in the negative electrode chamber being lower than the external pressure, the bonding surface between the negative electrode cover and the α-alumina ring is compressed, and the stress at the bonding interface is reduced. It is effective from the viewpoint of preventing the leakage of sodium without causing corrosion.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a negative electrode compartment structure for a sodium-sulfur battery of the present invention.

FIG. 2 is a cross-sectional view of a conventional negative electrode compartment structure for a sodium-sulfur battery.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solid electrolyte tube 2 α-alumina ring 3 negative electrode cover 4 positive electrode cover 5 negative electrode terminal 6 negative electrode current collector tube 7 metal fiber 8 sodium 9 concave portion 10 sealing body 11 opening

Claims (3)

[Claims] 1. An α-alumina ring is joined to an opening, a sodium ion conductive solid electrolyte tube having an inside as a negative electrode chamber, a negative electrode current collector tube having a lower part inserted into the negative electrode chamber, and a negative electrode current collector. The upper part of the electric tube is inserted into the negative electrode terminal, and one end is joined to the upper surface of the α-alumina ring, and the other end is formed by a negative electrode lid welded to the negative electrode terminal. A negative electrode chamber for a sodium-sulfur battery, wherein the negative electrode chamber is sealed and vacuum holding means is provided on the negative electrode current collector tube and the negative electrode terminal. 2. A vacuum holding means having a through hole formed at the bottom of the negative electrode terminal and having a closing body for closing the through hole, and a vacuum holding means for sealing the top of the recess. 2. A negative electrode compartment for a sodium-sulfur battery according to claim 1, comprising an opening provided in a portion of the negative electrode current collector tube located in the negative electrode chamber. 3. An α-alumina ring is joined to the opening, a negative electrode lid is joined to the upper surface of the α-alumina ring, and a sodium ion conductive solid electrolyte tube having an inside as a negative electrode chamber; Prepare a negative electrode current collector tube having a, a negative electrode terminal having a through hole at the bottom and a concave portion formed at the top with a recess provided with a closing body for closing the through hole,
Insert the upper part of the negative electrode current collector tube into the negative electrode terminal so that the inside communicates with the through hole of the negative electrode terminal, insert the lower part of the negative electrode current collector tube into the negative electrode chamber, and place the negative electrode terminal on the negative electrode lid. Welding, after filling sodium into the negative electrode chamber from the through-hole of the negative electrode terminal, evacuating the negative electrode chamber through the opening and the concave portion, and then sealing the negative electrode chamber, Production method.