JPS59228371A - Sodium-sulfur battery - Google Patents

Abstract

PURPOSE:To smoothly supply sodium form a sodium container to a solid electrolyte cylinder by installing a sodium path in the sodium electrolyte cylinder. CONSTITUTION:A shock absorber 15 is placed in the inner bottom of a solid electrolyte cylinder, and a sodium container 12 filled with sodium is inserted into it. An anode cover 10 having a welded anode pipe 14 is inserted and a sodium path 13 is inserted into the anode pipe 14. Then an anode auxiliary cover 3, the anode cover 10, and the upper end of the anode pipe 14 are welded. Thereby, one more path is formed between the sodium path 13 and the anode pipe 14. Even when electrical contact of the anode cover 10 and molten sodium 11 is cut by lack of sodium in the upper part, molten salt 11 is in contact with the anode pipe 14 to keep electrical contact. By forming one more path, path of sodium is narrowed, and supply of sodium is suppressed against quick consumption of sodium.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of the cathode chamber of a Nato IJ Umu sulfur battery.

As shown in FIG. 1, the conventional sodium yellow battery has a cathode auxiliary lid 6 on the top surface of an a-alumina ring 2 bonded to the top end of a sodium ion conductive solid electrolyte tube 1.
However, an anode lid 4 is bonded to the bottom surface by thermopressure via an aluminum layer. On the other hand, an anode conductive material 7 made of woven graphite or carbon fibers impregnated with sulfur as an anode active material 6 is inserted into the oil container 5 which also serves as an anode current collector, and an anode conductive material 7 is inserted at the bottom. A felt-like disk 8 made of the same material as material 7 was placed. The solid solute tube 1 is inserted into the battery container 5, and the anode lid 4 and the battery container 5 are welded together in a vacuum or under reduced pressure of helium gas, and the anode chamber is hermetically sealed. @ Regarding the electrode chamber, micropores are inserted into the bottom of the IIJi electrode support furnace 3 and the solid electrolyte tube 1.

The upper end of the sodium container 9 and the exhaust and cathode current collector terminal l
After welding, the cathode lid 10 is kept at a temperature of about 150°C, and a fixed amount of IJium (IJum is melted as the cathode active material 11 at the same temperature from the cathode current collector terminal t) by vacuum impregnation method is filled and cooled. do. After cooling, the upper end of the cathode current collector terminal is welded under an argon gas, nitrogen gas, or helium gas atmosphere to seal the cathode chamber. After filling the solid electrolyte tube 1 with sodium in this way, the battery container 5 and the anode lid 4 are welded together to create a battery having the cathode active material 11 and the anode active material 6. The conductive material 7 may be inserted from the bottom of the battery container 5, and then the bottom cover of the battery container 5 may be welded.

This conventional sodium-sulfur battery consists of a sodium container 9
When filling the solid electrolyte tube 1 with sodium 11, it is necessary to raise the temperature of the solid electrolyte tube 1 to a temperature higher than the melting point of sodium. Due to the heat cycle caused by this temperature increase and temperature decrease after filling, the glass solder joints between the solid electrolyte tube 1 and the α-alumina ring 2 may be damaged by thermal shock, and the sodium container 9
There is a hole in the bottom cover for sodium 11 to pass through,
If the pore diameter is small, during discharge, sodium supply from the inside of the sodium container 9 to the gap between the solid electrolyte tube 1 and the solid electrolyte tube 1 will be insufficient, resulting in an IJium deficiency point (which is the inner surface of the solid electrolyte tube 1), and the battery will be damaged. There are problems in that internal resistance increases and cracks occur in the solid electrolyte tube 1 due to non-uniform current density.

The present invention solves the above problems, and will be explained in detail below with reference to the drawings.

FIG. 2 is a sectional view of a sodium-sulfur battery according to an embodiment of the present invention, in which 1 is a solid electrolyte tube, 2 is an α-alumina ring, 3 is a cathode auxiliary lid, 4 is an anode lid, 5 is a battery container, and 6
is an anode active material, 7 is an anode conductive material, 8 is a felt-like disk,
I/)2v! Paar 1/1. Poison terminal (10 is a cathode lid, 11 is a cathode active material) 12 has a bottom lid 12' and a top lid 12',
In addition, as the sodium communication passage 13, for example, a container made of a stainless steel pipe with an inner diameter of 3φ and an outer diameter of 4φ welded to the upper lid 12',
The lower end of the sodium communication passage 13 is spaced apart from the bottom cover 12' by at least 1 fl. Top lid 12' or bottom lid 1 of container 12
2', the container 12 is filled with, for example, 20 to 120 caps of sodium azide wrapped in aluminum foil, and then the container 12 is heated in an inert gas atmosphere, such as nitrogen gas or argon. The temperature is kept at about 100-150°C in a gas atmosphere. After exhausting the sodium through the sodium communication passage 16 while keeping it warm,
Molten sodium is filled from the sodium communication path 13 by vacuum impregnation, and the container 12 is filled and cooled. 14 is a cathode pipe welded to the cathode lid 10, and the inner diameter is larger than the outer diameter of the sodium communication passage 13, for example, the inner diameter is 5φ and the outer diameter is 6φ.
A stainless steel tube with a sodium communication passage inserted inside. 15' is a shock absorbing material made of fibers such as stainless steel, carbon fiber, or metal-coated carbon, which also retains sodium. That is, for the cathode, after disposing the shock absorber 15 at the inner bottom of the solid electrolyte tube 1, insert the sodium-filled sodium container 12, then insert the cathode lid 10 to which the cathode pipe 14 is welded, and insert the cathode pipe 14 into the cathode pipe 14. After arranging the sodium communication passage 16 to be inserted, the cathode auxiliary lid 3 and the cathode lid 10 are removed in a vacuum or under reduced pressure containing a small amount of helium gas.
And the upper end of the cathode pipe 14 is welded. Note that the welding of the cathode pipe 14 may be performed after the welding of the cathode auxiliary lid 6 and the cathode lid 10 (which may be performed in air).

By configuring as described above, a gap serving as another communication path is formed between the sodium communication path 16 and the cathode pipe 14. Therefore, the battery operating temperature is about 300~
When the temperature rises to 650°C, the sodium 11 in the sodium container 12 expands, and as the internal pressure of the sodium container 12 increases, the molten sodium 11 is pushed upward through the sodium communication path 13 and fills the cathode pipe 14. After that, the solid electrolyte tube 1) fills the gap between the solid electrolyte tube 1 and the lithium container 12. When discharging, the molten sodium in the interstitial region is ionized and moves to the anode chamber through the solid electrolyte tube 1, which reduces the amount of sodium.Since the sodium communication passage 13 is inserted into the cathode pipe 14, for example, there is a sodium deficient area in the upper part. Even if this occurs and the electrical contact between the cathode lid 10 and the molten sodium 11 is broken, the contact with the molten sodium 11 is maintained through the cathode pipe 14, so the electrical connection will never be broken. Furthermore, the formation of a gap between the cathode pipe 14 and the sodium communication passage 16 narrows the sodium passage, so even if there is rapid sodium consumption, for example, a direct reaction with the anode active material 6 due to breakage of the solid electrolyte tube 1, the sodium container 12 The amount of sodium supplied from within is suppressed. Furthermore, the sodium container 12 is held by a shock absorber 15 at the bottom and a cathode pipe 14 at the top.
Since the sodium supply amount 16 is inserted inside and semi-fixed, there is no eccentricity, and there is no impact on the solid electrolyte tube 1 due to looseness or the like.

The table below shows improvements between the conventional battery and the battery of the present invention.

table Next, other embodiments will be described.

In the embodiment shown in FIG. 6, a sectional view of the cathode side is shown, and 9' is a cathode current collector terminal made of stainless steel or nickel, and 14' is a cathode current collector terminal made of stainless steel or nickel.
is a cathode rod welded to the cathode lid 10, which is made of stainless steel and has a diameter of 3φ, is inserted into the sodium communication passage 13 having an inner diameter of 4φ, and is in contact with the bottom fE 12' of the sodium container 12. This is done by filling the sodium container 12 with molten sodium by vacuum impregnation, and then inserting the cathode rod 14' of the cathode lid 10, to which the cathode rod 14' and the cathode current collector terminal 9' are welded, into the sodium communication path 16. Cooling.

Next, the sodium-filled sodium container 12 and the cathode lid 10 are inserted into the solid electrolyte tube 1, and the cathode shoe 1 is placed under vacuum.
0 and the cathode auxiliary lid 5 are welded.

With the above structure, the sodium in the sodium container 12 is at the lowest liquid level at the end of the discharge (for example, the sodium communication path 1
3)), even if the cathode bar 14
' is submerged in molten sodium, so electrical contact is always made.

Furthermore, even if the gaps formed between the side surfaces of the sodium communication path 13 and the cathode rod 14' are made smaller, the amount of sodium per unit area does not change, and the effect of suppressing rapid sodium consumption can be achieved. In the embodiment shown in Fig. 4, a cathode collector terminal 9' is welded by spot welding to the upper surface of the cathode cover 10' made of stainless steel with a thickness of about 0.5 mm, and a tapered terminal with a diameter of 2φ is attached to the lower surface. A cathode rod 14' made of a stainless steel rod (which may be in the shape of a wood screw) was welded by spot welding or the like. After filling the sodium container 12 with the cathode active material 11 as described above, the sodium container 12 is inserted into the solid electrolyte tube 1, and the cathode lid 10'
and the cathode rod 14' was inserted into the sodium communication path 13. Next, the cathode cover 10' and the cathode auxiliary cover 5 were welded together in a vacuum or under reduced pressure of helium gas to vacuum-seal the cathode chamber. With the above configuration, when the temperature rises to the battery operating temperature, the solid electrolyte tube 1, cathode cover 10', etc., and the sodium container 12
The gap between the battery and the battery is filled with molten sodium, and an electrical connection is established through contact between the molten sodium itself and the cathode cover 10' and the cathode rod 14', and no increase in battery internal resistance due to poor contact is observed during charging and discharging. (If this phenomenon occurs, the discharge pressure decreases even though the molten sodium remains in the sodium container 12 due to consumption, and the discharge is terminated. The battery capacity becomes smaller than the theoretical value and the battery characteristics deteriorate.) . Furthermore, the flow rate is suppressed by the gap between the cathode rod 14' and the sodium communication passage 15 against rapid sodium ram consumption. Furthermore, for normal sodium consumption, the tapered tip of the cathode rod 14' reduces the flow rate! Constant.

Note that the sodium container according to the present invention is not limited to the above-mentioned embodiments, and the material, wall thickness, shape, and material of the cathode nozzle rod are not limited to the single or double container.

As described above, the present invention reduces the number of heat cycles applied to the solid electrolyte tube, eliminates shock to the solid electrolyte tube due to eccentricity of the sodium container, and maintains electrical connection at all times in any state. In addition, it has the effect of suppressing the rapid supply of sodium when the battery is damaged, and has great industrial value.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional sodium-sulfur battery, and FIGS. 2, 6, and 4 are sodium-sulfur batteries according to embodiments of the present invention.
FIG. 2 is a cross-sectional view of a sulfur battery. 1...Solid electrolyte tube 9.12..., sodium container 13...sodium communication path 14...cathode vibrator 14', 14'...@Fence rod applicant Yuasa Battery Co., Ltd.! r4 diagram

Claims (1)

[Scope of Claims] 1) In a sodium-sulfur battery with an IJium ion-conducting solid electrolyte tube as a cathode chamber, a sodium container provided with a sodium communication path is arranged in the solid electrolyte tube,
A sodium-sulfur battery characterized in that at least a sodium communication path leading to a solid electrolyte tube is narrowed. 2) The sodium-sulfur battery according to claim 1, wherein one end of the sodium communication path is inserted into a cathode pipe with one end sealed. 3) The sodium-sulfur battery according to claim 1, wherein the cathode rod provided on the cathode cover is inserted into the sodium communication path. 4) The sodium-sulfur battery according to claim 3, wherein the cathode rod is inserted up to the vicinity of the inner bottom surface of the sodium container.