JPS617576A - Sodium-sulfur battery - Google Patents

Abstract

PURPOSE:To eliminate influence of temperature increase to an adjacent battery caused by breakage by arranging a mechanism by which supply of sodium is stopped when a solid electrolyte tube is broken, sodium directly reacts with sulfur, and temperature is increased, and connecting a battery to an adjacent battery by a connector which is directly installed in the battery. CONSTITUTION:The bottom of a sodium reservoir 11 is welded to the upper end of a metal tube 10. An anode pipe 12 for exhausting and sodium filling, which is vacuum-sealed after sodium filling, is welded to the upper part of the sodium reservoir 11. An anode terminal 13 is welded to the outer lower side of the sodium reservoir 11. A filler 17 which is resistant to molten sodium is filled in a space formed by the inside of an inner insertion tube 20 and the outside of the metal tube 10. If a solid electrode tube is broken, direct reaction of sodium with sulfur is eased by the filler 17. When temperature is increased by continued reaction, a copper or aluminum rod 14 inserted inside the metal tube 10 is melted and blocks a passage of sodium to stop the supply of sodium.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sodium-sulfur battery which is constructed by connecting a large number of batteries in series and parallel to obtain large capacity and high voltage.

Prior art and its problems As shown in Figure 3, a sodium-sulfur battery for connecting a large number of batteries in series and parallel has a cathode active material 3 inside a sodium ion conductive solid electrolyte tube 1 made of β'-alumina. A metal fiber 2 made of sodium-impregnated stainless steel, iron, aluminum, porcelain, etc. and a cathode current collector terminal 8 are inserted. A cathode cover 4 to which an a-alumina ring 9 is glass-bonded is welded to the cathode current collector terminal 8.
Nickel steel II welded to the cathode current collector terminal 8 on the top surface.
j5 is welded, and furthermore, a cathode terminal 6 is connected to the tip of the nickel steel wire 5. The cathode terminal 6 is used to electrically connect the battery with instantaneous contact, and the nickel steel! 5 absorbs thermal strain and mechanical shock at high temperatures. However, when passing a large current, nickel steel fj! If 5 is long, the voltage drop will be large, and if it is short, the absorption effect of thermal strain etc. will be poor, and if the solid electrolyte tube is broken, a large amount of heat will be released and the adjacent battery will also be damaged.

OBJECTS OF THE INVENTION It is an object of the present invention to minimize the voltage drop by eliminating connections between adjacent batteries, and to limit the effects of damage to only the damaged battery.

Structure of the Invention The present invention supplies sodium, which contributes to battery reactions, from a sodium reservoir attached to the top of the battery. At the same time, the battery is connected to an adjacent battery through a connecting body directly attached to the battery, and the battery body is provided with a mechanism for absorbing thermal strain and mechanical shock.

Embodiment FIG. 1 is a cross-sectional view of a sodium-sulfur battery according to an embodiment of the present invention. In FIG. -250r-45l, mul coated 'He
The cathode auxiliary lid 19 consisting of
An inner tube 2° made of a molten sodium-resistant metal such as stainless steel and having a wall thickness of about 0.3 m to 2 tm is welded to 119 and inserted into the solid electrolyte tube 1, thereby connecting the solid electrolyte tube 1 and the inner tube 20. It forms a gap of 0°5 to 2H.

A metal tube 1o forming a sodium passage is welded to the bottom of the inner tube 2o, the lower end of the metal tube 10 communicates with the inside of the solid electrolyte tube 1, and the upper end stores sodium 3 necessary for discharge. It communicates with the inside of the reservoir 11.

The bottom of the sodium reservoir 11 is welded to the top end of the metal tube 1°, and the cathode pipe 12 for filling +J is welded to the top of the sodium reservoir 11, which also serves as a vacuum-sealed exhaust after filling with sodium. The cathode terminal 13 is made of stainless steel, stainless steel coated steel, and stainless steel coated copper and is welded to the stainless steel coated steel.The structure of the cathode terminal 13 is as shown in the cross-sectional view of Fig. 2. The sodium reservoir 11 is made of a molten sodium-resistant metal such as stainless steel with a wall thickness of 0.4 fl to 1 R, and a buffer material 18 such as a spring 1 washer or a heat insulating material is arranged between it and the cathode auxiliary lid 19. .

Reference numeral 14 is a copper or aluminum rod inserted into the sodium passageway in the metal tube 10 to restrict the flow rate of sodium and to assist in collecting it.

In addition to applying electricity, the protrusion on the upper part connects the metal tube 10.
suspended from the top. Reference numeral 15 denotes a battery case that also serves as an anode current collector, and an anode terminal 16 is welded to the outer side surface. 1
7 is a molten sodium-resistant filling material filled in the space formed between the inside of the inner tube 20 and the outside of the metal tube 10, such as metal fiber, sodium carbonate powder, sodium chloride powder, vermiculic acid powder* , calcium carbonate powder, α-alumina powder, sand, corundum, etc.
In the sodium-sulfur battery having the above structure, the sodium reservoir 11 is fixed only at the lower end of the metal tube 10, so that mechanical shock and thermal strain can be easily absorbed. Furthermore, even when the cathode terminals 13 are connected to adjacent batteries, thermal distortion of the cathode terminals can be absorbed, and adjacent batteries can be directly connected, minimizing voltage drop. can. Further, by disposing the cushioning material 18, the effect of absorbing mechanical shock can be enhanced when necessary. Furthermore, if the solid electrolyte tube 1 is damaged, while the direct reaction between sodium and sulfur is alleviated by the filling material 17, the reaction continues.
When the battery temperature rises, the copper or aluminum rod 14 inserted into the metal tube 10 melts, blocking the sodium passage and stopping the supply of sodium. For this reason, the direct reaction is stopped, and the influence on adjacent cells due to temperature rise can be prevented.Examples will be further explained below◇ β'-
Inside the alumina solid electrolyte tube 1 is an outer diameter of 29 mm, a wall thickness of 1 mm,
A stainless steel inner tube 20 with a length of 3 Q cm, a stainless steel inner tube 10 with an outer diameter of 6 fl and a wall thickness of 0.51111 welded to the inner tube 20 at the center of the bottom, and welded to the upper end of the metal tube 10. It has a stainless steel sodium reservoir 11 with an outer diameter of 50.8 mm and a wall thickness of 0.5 mm, and a filling material 17 made of aluminum fiber is arranged, and about 195 g of sodium 3 was injected into the sodium reservoir 11 and cooled, and the tip of the cathode pipe 12 was vacuum welded to vacuum-seal it. The lower part of the outer surface of the sodium resolver 11 has a thickness of 3 m as shown in Figure 2.
It has a nickel-coated cathode terminal about 25 μm thick on a copper plate 30 cm wide. The time required to connect 6 cells in parallel with this battery was approximately 4.5 minutes with conventional batteries,
It took about 2 minutes 〇Also, 1 cell out of 6 cells was destroyed,
There was no abnormality in the battery case, and a large amount of sodium 3 remained in the sodium reservoir.

Next, with the same structure as the previous embodiment, sodium carbonate powder is placed as the filling material 17, an aluminum rod 14 with an outer diameter of 4wx is placed inside the metal tube 10, and an inner tube 20 with an outer diameter of 29mm is placed inside the metal tube 10.
tm, 0.2 mm thick stainless steel tube, 6 cells were connected in parallel, and overvoltage was applied to destroy 1 cell out of the 6 cells.

When the battery was destroyed and a normal charge/discharge test was performed, no short circuit occurred. After cooling and disassembling the battery,
Sodium remains in the sodium reservoir 11,
A hole was made in the inner tube 20, and the aluminum rod 14 was melted inside the metal tube 10 at a position facing the hole.

Effects of the Invention As detailed in the Examples, the sodium according to the present invention
Sulfur batteries can be connected between batteries without using connectors, which minimizes voltage drop during charging and discharging of large currents, and reduces the effect on adjacent batteries of temperature rise when damaged. By making the battery itself flexible, the effect of absorbing mechanical shock and thermal strain is enhanced.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of the sodium-sulfur battery of the present invention, Fig. 2 is a cross-sectional view of a sodium reservoir having a cathode terminal, and Fig. 3 is a longitudinal cross-sectional view of a conventional sodium-sulfur battery. ...Solid electrolyte tube 3...Sodium 6.1
3... Cathode terminal 9... α-alumina ring 10... Metal tube 11... Sodium reservoir 14... Copper or aluminum rod 17... Filling material 18... Buffer material 19. ...Cathode auxiliary lid 2
0...Internal intubation

Claims (6)

[Claims] (1) An inner tube welded to a cathode auxiliary lid bonded to the top surface of an a-alumina ring glass-bonded to the top of the solid electrolyte tube, and a metal tube to which the bottom and lower end of the inner tube are welded; A sodium reservoir is provided above the inner tube, the upper end and the bottom of which are welded together, and the inside of the sodium reservoir, the metal tube, and the inside of the solid electrolyte tube communicate with each other, and the outside of the inner tube and the solid electrolyte tube are in communication with each other. A sodium-sulfur battery characterized in that sodium interposed in a gap between the inside of an electrolyte tube and the cathode active material is used as a cathode active material. (2) The sodium-sulfur battery according to claim 1, wherein the metal tube and the inner tube extend to near the bottom of the solid electrolyte tube. (3) Claims 1 and 2, characterized in that a rod made of copper or aluminum is inserted into the metal tube.
Sodium-sulfur battery as described in . (4) The gap between the outside of the metal tube and the inside of the inner tube communicates with the outside of the battery, and the gap is filled with metal fibers as a filling material.
Claims 1 to 3 are filled with a substance selected from sodium carbonate powder, vermiculite powder, calcium carbonate powder, a-alumina powder, sand, corundum, etc. sulfur battery. (5) A sodium-sulfur battery according to any one of claims 1 to 4, characterized in that the battery has a cathode terminal on the outer lower side surface of the sodium reservoir. (6) The sodium-sulfur battery according to any one of claims 1 to 5, further comprising a buffer material in the gap between the bottom of the sodium reservoir and the top surface of the cathode auxiliary lid.