JP3095909B2 - Method for producing sodium-sulfur battery and anode container thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sodium-sulfur battery and its anode container.

[0002]

2. Description of the Related Art In general, in a sodium-sulfur battery, an anode container is formed of a metal material such as aluminum or an aluminum alloy, and a solid electrolyte tube made of ceramic such as beta alumina is suspended in the anode container. Is being worn. Then, sodium is contained in the cathode chamber inside the solid electrolyte tube, and sulfur is contained in the outside anode chamber.

In this type of sodium-sulfur battery, it is heated to 300 to 350 ° C. during operation, and
When stopped, heat is dissipated and cooled. At this time, since the metal anode container has a larger coefficient of thermal expansion than the ceramic solid electrolyte tube, the gap between the anode container and the lower end portion of the solid electrolyte tube increases during operation, and the gap decreases when stopped. Become.

However, when the sodium polysulfide in the molten state during operation is cooled to around 240 ° C., it solidifies and forms a solid phase in the gap between the anode container and the lower end of the solid electrolyte tube. Cannot be shrunk to the original size when cooled. For this reason, when the operation-stop of the battery is repeatedly performed, the anode container may gradually elongate in the axial direction and damage the solid electrolyte tube.

[0005] In order to solve such a problem, a sodium-sulfur battery in which one constriction is provided near the upper end of the outer periphery of the anode container so as to absorb and reduce expansion and contraction of the anode container due to heat change is also known. It has been conventionally proposed.

[0006]

However, in this conventional sodium-sulfur battery, only one constriction is provided in the vicinity of the upper end of the outer periphery of the anode container. The accompanying expansion and contraction cannot be sufficiently absorbed and alleviated. For this reason, when the battery is repeatedly operated and stopped, the constricted portion excessively expands or contracts due to a thermal change, and cracks occur in the constricted portion and the corrosion-resistant coating on the inner surface of the anode container, or the solid electrolyte tube may be damaged. There was a problem of being damaged.

[0007] The present invention has been made in view of the problems existing in such a conventional technique, and its first aspect is as follows.
The purpose of this method is to sufficiently absorb and mitigate the expansion and contraction of the anode container due to thermal changes, and when the battery is repeatedly operated and stopped, the constriction on the outer periphery of the anode container and the corrosion-resistant coating on the inner surface of the anode container It is an object of the present invention to provide a sodium-sulfur battery that can surely prevent the occurrence of cracks and breakage of the solid electrolyte tube.

A second object of the present invention is to provide an anode container for a sodium-sulfur battery which can easily produce an anode container having a plurality of constrictions on the outer periphery without cracks or the like occurring in the constrictions. An object of the present invention is to provide a method for manufacturing a container.

[0009]

In order to achieve the first object, according to the first aspect of the present invention, a ceramic solid electrolyte tube is suspended in a metal anode container. A sodium-sulfur battery containing sodium in the cathode chamber inside the solid electrolyte tube and sulfur in the outside anode chamber, providing a constricted portion on the upper outer periphery of the anode container, A further constricted portion is formed at a predetermined interval downward from the portion.

In order to achieve the second object, according to the second aspect of the present invention, a ceramic solid electrolyte tube is attached to a metal anode container in a suspended state,
In a sodium-sulfur battery containing sodium in the cathode chamber inside the solid electrolyte tube and sulfur in the outside anode chamber, a straight tubular metal pipe is heated until the Vickers hardness becomes smaller than 40. In this state, a plurality of constrictions are formed on the outer periphery of the metal pipe at predetermined intervals in the longitudinal direction.

[0011]

In the sodium-sulfur battery configured as described above, when the battery is repeatedly operated and stopped to expand or contract the anode container due to heat change, the expansion and contraction of the anode container is vertically positioned. The absorption is surely alleviated by sharing to a plurality of constrictions. Therefore, it is possible to reliably prevent the occurrence of cracks in the constricted portion on the outer periphery of the anode container and the corrosion-resistant coating on the inner surface of the anode container and the possibility of breakage of the solid electrolyte tube.

In the case of manufacturing an anode container, a straight metal pipe is subjected to heat treatment until the Vickers hardness becomes smaller than 40, and then a plurality of constrictions are formed on the outer periphery of the metal pipe at predetermined intervals in the longitudinal direction. If formed, the anode container can be easily manufactured without generating cracks or the like in the constricted portion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a sodium-sulfur battery embodying the present invention will be described in detail with reference to the drawings.

As shown in FIGS. 1 and 2, the anode container 1 is formed in a cylindrical shape from a metal material such as aluminum or an aluminum alloy, and a bottom plate 2 is fitted and fixed to an opening at a lower end thereof. A pair of upper and lower constrictions 3 and 4 are formed on the outer periphery of the anode container 1 at predetermined intervals in the longitudinal direction, and the constrictions 3 and 4 absorb and reduce expansion and contraction of the anode container 1 due to a heat change. In addition, the lower constricted part 4 is provided above the lower part, avoiding sodium polysulfide (Na ₂ S _X ) as an active material accumulated at the lower end. The corrosion-resistant coating 5 is formed by spraying on the inner peripheral surface of the anode container 1, and the corrosion-resistant coating 5 prevents corrosion of the anode container 1.

The support bracket 6 is fitted and fixed to the upper end opening of the anode container 1, and an insulating ring 7 made of alpha alumina is fixedly joined to the upper surface thereof. A cylindrical solid electrolyte tube 8 having a bottom and made of a ceramic material such as beta-alumina is suspended and fixed to the inner periphery of the lower end of the insulating ring 7 in a suspended state. Inside the solid electrolyte tube 8, a cathode chamber R1 is defined. At the same time, an anode chamber R2 is defined on the outside.

A cartridge 9 is provided in the cathode chamber R1, and contains sodium Na as a cathode active material. The small hole 10 is provided at the bottom of the cartridge 9, and the sodium Na in the cartridge 9 is supplied to the gap between the cartridge 9 and the solid electrolyte tube 8 through the small hole 10.

Inert gas G such as nitrogen gas or argon gas
Is sealed in the upper space of the cartridge 9 at a predetermined pressure, and the inert gas G pressurizes sodium Na in the cartridge 9 in a direction of flowing out of the small holes 10. The anode conductive material 11 made of a carbon mat or the like is accommodated in the anode chamber R2, and the anode conductive material 11 is impregnated with sulfur S as an anode active material.

The cathode lid 12 is fixedly joined to the insulating ring 7 and has a central disk portion 13 and a cylindrical portion 14 provided on the outer periphery of the disk portion 13. The lower end of the cylindrical portion 14 of the cathode lid 12 is connected to the sodium Na supplied to the gap between the cartridge 9 and the solid electrolyte tube 8.
, And current collection on the cathode side is performed.

The bottomed cylindrical safety tube 15 is disposed in the gap between the cartridge 9 and the solid electrolyte tube 8 at a predetermined interval from the cartridge 9 and the solid electrolyte tube 8, respectively, and has corrosion resistance. It is formed from a metal material such as aluminum or stainless steel. Then, after the sodium Na supplied from the small hole 10 of the cartridge 9 at the time of discharge is moved upward in the gap between the safety tube 15 and the cartridge 9, it passes over the upper end of the safety tube 15 and It is moved downward in the gap between the tube 15 and the solid electrolyte tube 8. Further, the sodium Na permeates through the solid electrolyte tube 8 as sodium ions, and the anode room R
It is designed to be moved to two sides.

Next, the operation of the sodium-sulfur battery of this embodiment configured as described above will be described. Now, this battery is heated to 300-350 ° C during operation,
In this state, sodium Na in the cathode chamber R1 and sulfur S in the anode chamber R2 are ionized. Then, the ionized sodium permeates through the solid electrolyte tube 8 during discharge and moves to the anode chamber R2 side, and reacts with sulfur S to generate sodium polysulfide. Conversely, during charging, sodium polysulfide is decomposed, and the generated sodium ions are transferred to the solid electrolyte tube 8.
To generate sodium Na on the cathode chamber R1 side and sulfur S on the anode chamber R2 side.

As described above, the battery is operated during operation at 300-35.
While being heated to 0 ° C., it is cooled by radiating heat when stopped. At this time, the anode container 1 made of a metal material such as aluminum or an aluminum alloy has a larger coefficient of thermal expansion than the solid electrolyte tube 8 made of a ceramic material such as beta-alumina. The gap with the lower end is enlarged, and this gap is reduced when stopping.

However, when the sodium polysulfide in the molten state during operation is cooled to around 240 ° C., it solidifies and forms a solid phase in the gap between the anode container 1 and the lower end of the solid electrolyte tube 8. The anode container 1 cannot be contracted to its original size during cooling. For this reason, when the operation-stop of the battery is repeatedly performed, the anode container 1 may gradually expand in the axial direction, and the solid electrolyte tube 8 may be damaged.

However, the sodium-
In the sulfur battery, since a pair of upper and lower constricted portions 3 and 4 are formed on the outer periphery of the anode container 1 at predetermined intervals in the longitudinal direction, the operation and stop of the battery are repeated, and the anode container 1 is heated. Even when the anode container 1 is expanded or contracted by the change, the expansion and contraction of the anode container 1 is controlled by a pair of upper and lower constricted portions 3 and 4.
And the absorption is surely alleviated. Therefore, the anode container 1
Cracks in the constricted portions 3 and 4 on the outer periphery of the outer wall and the corrosion-resistant coating 5 on the inner surface of the anode container 1 and damage to the solid electrolyte tube 8 can be reliably prevented.

Incidentally, the configuration of the embodiment in which a pair of upper and lower constricted portions 3 and 4 are provided on the outer periphery of the anode container 1, the configuration of the conventional example in which only the upper constricted portion 3 is provided on the outer periphery of the anode container 1, and the anode container The upper constriction 3 is provided on the outer periphery of the
The relationship between the number of heat cycles and the number of cracks generated in the upper constricted portion 3 was tested with respect to the configuration of the comparative example in which the circular constricted portion was provided in the disk portion 13 of FIG. The result was obtained. As is clear from this graph, it was confirmed that the number of cracks in the upper constricted portion 3 can be significantly reduced according to the configuration of this example, as compared with the configurations of the conventional example and the comparative example.

Similarly, the relationship between the number of heat cycles and the number of cracks generated in the corrosion-resistant coating 5 was tested for the configurations of this example, the conventional example, and the comparative example by an actual battery test, as shown in the graph of FIG. The result was obtained. As is clear from this graph, it was confirmed that the number of cracks in the corrosion-resistant coating 5 can be significantly reduced according to the configuration of this example, as compared with the configurations of the conventional example and the comparative example.

Next, an embodiment of a method of manufacturing an anode container embodying the invention described in claim 2 will be described with reference to FIG. That is, in this embodiment, when the anode container 1 is manufactured, the straight tubular metal pipe is heated until the Vickers hardness becomes smaller than 40, and then a pair of upper and lower constricted portions 3 is formed on the outer periphery of the metal pipe. , 4 are drawn while rotating at predetermined intervals in the longitudinal direction. With such processing, the anode container 1 can be easily manufactured without generating cracks or the like in the constricted portions 3 and 4. Further, after this processing, it is desirable that the vicinity of the constricted portions 3 and 4 be locally reheat-treated so that the entire anode container 1 has a uniform hardness.

Incidentally, the outer diameter is 60 mm and the length is 360
In the case where a pair of constrictions 3 and 4 having an inner diameter of 47 mm are formed on an aluminum pipe having a thickness of 2.2 mm and a wall thickness of 2.2 mm, the heat treatment temperature of the metal pipe for the anode container with respect to the presence or absence of defects in the constrictions 3 and 4 When the relationship with the pipe hardness was tested, the results shown in the graph of FIG. 5 were obtained.

As is apparent from this graph, the metal pipe was heat-treated at a temperature lower than 400 ° C. for 3 hours, and the constricted portion 3 was formed while the Vickers hardness was higher than 40.
In the case where No. 4 was drawn, defects such as cracks occurred in the constricted portions 3 and 4 after processing. On the other hand, when the metal pipe is heat-treated at a temperature higher than 400 ° C. for 3 hours and the Vickers hardness becomes smaller than 40, and the constrictions 3 and 4 are formed by drawing, the constriction after processing is obtained. Parts 3, 4
No cracks or other defects occurred.

[0029]

Next, another embodiment of the present invention will be described with reference to FIGS.

In these other embodiments, the constricted portion 4 is formed on the outer periphery of the anode container 1 by cutting. In the second embodiment shown in FIG. 6, the constricted portion 4 is formed by cutting into one annular groove having a substantially semicircular cross section. Further, in the third embodiment shown in FIG. 7, the constricted portion 4 is formed by one annular groove having a substantially arc-shaped cross section.
In the fourth embodiment, the constricted portion 4 has a substantially elliptical cross section.
It is formed by two annular grooves. Further, the fifth type shown in FIG.
In the embodiment, the constricted portion 4 is formed by two annular grooves having a substantially semicircular cross section. In the sixth embodiment shown in FIG. 10, the constricted portion 4 is formed by a plurality of annular grooves having a corrugated cross section.

The present invention is not limited to the configuration of the above-described embodiment. For example, the lower constricted portion 4 may be provided in the outer periphery of the anode container 1 in the vicinity of an intermediate portion in the longitudinal direction, or the arc of the lower constricted portion 4 may be formed. The configuration of each part is arbitrarily changed within a range not departing from the gist of the present invention, such as changing the size of the part according to the diameter and thickness of the anode container 1 and providing the lower neck part 4 at a plurality of places. It is also possible to convert.

[0032]

Since the present invention is configured as described above, it has the following excellent effects.

According to the first aspect of the present invention, the expansion and contraction of the anode container due to the thermal change can be sufficiently absorbed and alleviated, and when the battery is repeatedly operated and stopped, the outer periphery of the anode container can be removed. It is possible to reliably prevent the occurrence of cracks in the constricted portion and the corrosion-resistant coating on the inner surface of the anode container and the possibility of breakage of the solid electrolyte tube.

According to the second aspect of the present invention, an anode container having a plurality of constrictions on the outer periphery can be easily manufactured without generating cracks or the like in the constrictions.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a sodium-sulfur battery embodying the present invention.

FIG. 2 is a longitudinal sectional view showing the anode container taken out.

FIG. 3 is a graph showing the relationship between the number of heat cycles in an actual battery test and the number of cracks in the upper constricted portion.

FIG. 4 is a graph showing the relationship between the number of heat cycles in an actual battery test and the number of cracks in a corrosion-resistant film.

FIG. 5 is a graph showing a relationship between a heat treatment temperature and a pipe hardness of a metal pipe for an anode container with respect to the presence or absence of a defect in a constricted portion.

FIG. 6 is a longitudinal sectional view of an anode container showing a second embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of an anode container showing a third embodiment of the present invention.

FIG. 8 is a longitudinal sectional view of an anode container showing a fourth embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of an anode container showing a fifth embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of an anode container showing a sixth embodiment of the present invention.

[Explanation of symbols]

1 ... anode container, 3 ... upper constricted part, 4 ... lower constricted part, 5 ...
Corrosion resistant coating, 8: solid electrolyte tube, R1: cathode chamber, R2: anode chamber, Na: sodium, S: sulfur.

Claims (2)

(57) [Claims] A ceramic solid electrolyte tube is suspended in a metal anode container, sodium is contained in a cathode chamber inside the solid electrolyte tube, and sulfur is contained in an outer anode chamber. In the sodium-sulfur battery housed, while providing a constricted part on the upper outer periphery of the anode container,
A sodium-sulfur battery in which another constricted portion is formed at a predetermined interval downward from the constricted portion. 2. A ceramic solid electrolyte tube is suspended in a metal anode container, sodium is contained in a cathode chamber inside the solid electrolyte tube, and sulfur is contained in an outer anode chamber. In the accommodated sodium-sulfur battery, the straight tubular metal pipe is subjected to heat treatment until the Vickers hardness becomes smaller than 40, and in this state, a plurality of constrictions are formed on the outer periphery of the metal pipe at predetermined intervals in the longitudinal direction. A method for manufacturing an anode container of a sodium-sulfur battery, characterized by being formed by: