JPH02201874A - Sodium-sulfur battery - Google Patents

Abstract

PURPOSE:To completely seal the upper part of a passing through hole, and to fuse an anode current collector when a battery is broken to separate the battery by inserting the anode current collector having a groove in the upper part into a passing through hole of an anode terminal wellded to an anode cover, and filling sodium through the groove, thin sealing. CONSTITUTION:An anode terminal 5 is welded to an anode cover 3 so as to cover the upper open end of a solid electrolyte tube 1, and a passing through hole 5' is installed in the center of the terminal 5. An aluminium anode current collector 6' having a groove 6'' in its one end is inserted into the hole 5' and the other end of current collector 6' is inserted into a cylinder comprising at least two metal fiber layers 12-1, 12-2. The groove 6'' is deformed and sodium 8 is filled in vacuum into an anode chamber through an upper hole 6A and a side hole 6B. A cylinder 5'' is installed in the upper part of the passing through hole 5'', and an anode terminal cover 14 is inserted into the cylinder 5'., then the anode chamber is sealed by vacuum welding. A container 9 inside which a sulfur molding 10 is placed is fitted from the lower side of the tube 1 and the upper end is welded to a cathode auxiliary cover 13, then a cathode chamber is sealed. The upper part of the passing through hole is completely sealed. When a battery is broken, the anode current collector is fused to separate the battery.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sodium-sulfur battery, and more particularly to a structure that prevents damage, improves safety, and facilitates filling with sodium.

Conventional technology and its problems Sodium-sulfur batteries have a completely sealed structure in which sodium as a cathode active material and sulfur as an anode active material are separated by a sodium ion conductive solid electrolyte tube such as r-alumina. It is a high-temperature secondary battery.

The conventional structure of such a F-sulfur battery will be explained with reference to FIG. An α-alumina ring 2 is bonded to the upper end of the solid electrolyte tube 1 by glass soldering, and a cathode cover 3 is bonded to the upper surface of the α-alumina ring 2, and an anode cover 4 is bonded to the lower surface thereof by heat pressure. A cathode terminal 5 is welded to the cathode lid 3, and a cathode vibro serving as a cathode current collector is welded through the center of the cathode lid 3, and the lower part thereof is inserted into the solid electrolyte tube 1.

Metal fibers 7 are disposed inside this solid electrolyte tube 1, and approximately 15
After evacuating the inside of the solid electrolyte tube 1 from the cathode vibro while keeping the temperature at 0°C, sodium 8 melted at the same temperature.
is vacuum filled, and the upper end of the filling machine cathode terminal 5 is sealed. Such a cathode chamber structure consists of a cylindrical sulfur molded body 10.
is pushed inward and inserted into the battery case 9 which also serves as a cathode current collector to which the anode current collector terminal 11 is welded.The anode current collector terminal 11 is bent outward and its upper end is vacuum welded to the anode lid 4. completely sealed.

In the lithium-sulfur battery having the structure described above, the sulfur molded body 10 thermally expands during the process of increasing the temperature to the operating temperature of 350° C., and the solid electrolyte tube 1 is subjected to bending stress. However,
Since the solid electrolyte tube 1 is firmly joined to the α-alumina ring 2 by glass solder, the solid electrolyte tube 1 may be damaged at the glass solder joint due to the bending stress. When the solid electrolyte tube 1 is damaged in this way, sulfur and sodium react directly, the internal pressure increases, and the cathode lid 3
There is a problem in that the active material peels off from the upper surface of the α-alumina ring 2, and the active material leaks out, damaging a normal battery that follows, resulting in a large-scale accident. In addition, since sodium 8 is vacuum-filled from the upper end of the cathode terminal 5, +3 um may adhere to the inside of the filling machine cathode terminal 5.
There is a problem in that the upper end of the Pji electrode terminal 5 is not completely sealed, resulting in defects.

Furthermore, when welding the anode current collector terminal 11 to the battery case 9, there is a problem in that the opening of the battery case 9 is eccentric due to the influence of heat, resulting in defective welding with the anode cover 4.

Purpose of the Invention The present invention solves the above-mentioned drawbacks by fitting a cathode current collector having a groove in the upper part into the through hole of the cathode terminal welded to the cathode cover, and filling sodium through the groove. The purpose of this is to completely seal the upper part of the through hole, and also to cut off the damaged battery by melting the cathode current collector when the battery is damaged.

Structure of the Invention The IJ Umu sulfur battery of the present invention has at least two layers of cylindrical metal fiber arranged in the cathode chamber, and α-
A convex part is provided on the upper surface of the alumina ring, an anode cover is thermo-pressure bonded to the outside of this convex part, this anode cover and the battery case are welded together via an anode auxiliary cover, and a cathode cover is attached to the inside of the convex part. A cathode terminal with a through hole is welded to the cathode lid, and a cathode current collector having a groove is inserted into the through hole.
The other end of the cathode current collector is inserted into the cylinder of the metal fiber to seal the cathode chamber.

EXAMPLES The present invention will be explained below using examples. FIG. 1 is a sectional view of the main parts of the sodium-sulfur battery of the present invention, and parts common to those in FIG. 5 are given the same reference numerals.

In FIG. 1, the solid electrolyte tube 1 has an outer diameter of 56 gl51, an inner diameter of 50 gl, and a length of 170 gl, with its top open.
- made of alumina, with an outer diameter of 76111 mm at its upper open end;
8. An α-alumina ring 2 having an inner diameter of 50 mm and a thickness of 10 mm is joined by glass soldering. A convex portion 2' is provided on the upper surface of this α-alumina ring 2, and a cathode cover 3 is bonded to the inside of this convex portion 2', and an anode cover 4 is bonded to the outside thereof by heat pressure to prevent mutual short circuit. The anode cover 4 is welded to an anode auxiliary cover 15 having a concentric corrugated portion. Further, the cathode cover 5 has an N-cathode terminal 5 so as to cover the upper open end of the solid electrolyte tube 1.
is welded, and a through hole 5 with a diameter of 7 cm is formed in the center of the cathode terminal 5.
', and this through hole 5' is provided with
A cathode current collector 6' made of aluminum having an outer diameter of 9 ms and a length of 17011 m and having a groove 6' with a depth of 5 m, a width of 2 vg, and a length of 40 m is inserted into one end, and the other Cylindrical metal fiber 12-1.12 consisting of at least two layers at the end
1a from the inner bottom of the solid electrolyte tube.
■Position above. By fitting the cathode current collector 6' into the through hole 5'lc in this way, the periphery of the groove 6I of the cathode current collector 6' is deformed to form the upper hole 6A and the side hole 6B, as shown in FIG. 4(b). are formed, and the upper hole 6M and the side hole 6B
Sodium 8 is vacuum filled into the cathode chamber via the . The filled sodium 8 also enters the cylinder of the metal fiber 12-L12-2 and comes into electrical contact with the cathode current collector 6'.

The metal fiber 12-1 is a stainless steel fabric (fiber diameter 8 μm) with an inner diameter of 18 m, an outer diameter of 20 m, and a height of 140 m. It is fixed by winding it so that it looks like this. A cylindrical part 5' is formed in the upper part of the cathode terminal 50 through hole', and a cathode terminal cover 14 having a threaded part on the inside is inserted into this cylindrical part 5' and vacuum welded to seal the cathode chamber. At the same time, one cathode connecting terminal 15 is screwed onto the threaded portion with a bolt 15'.

On the other hand, a battery case 9 into which a cylindrical sulfur molded body 10 is inserted is attached from below the solid electrolyte tube 1, and the upper end is welded to the anode auxiliary lid 13 to seal the anode chamber. Weld the battery case lid 17 to which the anode terminal 16 is connected to WI,
An anode connecting terminal 18 is tightened to the anode terminal 16 with a nut to form a completed battery.

Second! l! J is a sectional view of essential parts of a F-sulfur battery according to another embodiment of the present invention, in which parts common to those in FIG. 1 are given the same reference numerals. In the sodium-sulfur battery shown in FIG. 2, the concave portion of the cathode terminal cover 14 for sealing the cathode chamber is melted at the battery operating temperature! ! A metal 19 such as lead or a lead-tin alloy is placed on the positive side, and the cathode terminal 5 is extended upward through the metal 19 by an extension member 5m. An insulating member 20 is provided on the periphery of the extension member 5m, and this insulating member 2
0 to the battery case lid 17, and the other end of the battery case lid 17 is welded to the battery case 9 to seal the anode chamber.

In the IJ Umu sulfur battery according to the present invention, 1 anode auxiliary lid 1
3 and FIG. 2, the metal 19, which is in a molten state at the battery operating temperature, causes the cathode connection terminal 15 and the V7h electrode connection terminal 18 to
It can be made flexible, making it particularly suitable for electric vehicles that generate a lot of vibration.

Now, we manufactured 10 cells each of the battery of the present invention as shown in Fig. 1 and the conventional battery as shown in Fig. 3, and set the room temperature to 350°C.
A heat cycle test was conducted at a temperature increase/decrease rate of approximately 150° C. to 200° C./h, and the results are shown in Table 1. In Table 1, the numerator indicates the number of batteries from which active material leaked, and the denominator indicates the number of damaged batteries. Note that when a battery is damaged, the voltage drops rapidly, so the damaged battery was removed by the drop in voltage.

Margin below! -1 Table 1 shows that conventional batteries often break during heat cycle testing up to 10 cycles, and even when they break, active materials leak out and two-thirds of the batteries are short-circuited.
No damage was observed in the battery of the present invention during heat cycle tests up to 10 cycles.

Next, the batteries that were not damaged were subjected to a battery destruction test by overcharging at 550°C, and the results are shown in Table 2.

Table 2 From Table 2, while the conventional battery was damaged and short-circuited, the battery of the present invention was short-circuited.

Further, similar experiments were conducted on the battery of the present invention as shown in FIG. 2, but the results were the same.

Effects of the Invention As described in detail in the examples, the battery of the present invention is equipped with an anode auxiliary lid to transfer stress-induced displacement upwards of the solid electrolyte tube. can be absorbed and prevent damage to the solid electrolyte tube. Furthermore, even if the battery is damaged, the cathode current collector 6' is fused due to the heat of the direct reaction between sodium and sulfur, so that short circuits can be prevented from occurring inside the damaged battery.

Furthermore, it is possible to prevent sodium from adhering to the inside of the cathode terminal during filling with sodium.

[Brief explanation of the drawing]

Figures 1 and 2 are sectional views of essential parts of the sodium-sulfur battery of the present invention, Figure 5 is a sectional view of a conventional lithium-sulfur battery, and Figure 4 (~, middle) is a cross-sectional view of the cathode current collector. FIG. 1...Solid electrolyte tube 2...Protrusion 4...Anode cover 5'...Through hole 5A...Extension member 6'...Groove 6B...Side hole 7! 15...Vh pole auxiliary cover 17...Battery container cover 20...Insulating member

Claims (3)

[Claims] (1) An α-alumina ring is bonded to the upper end of a sodium ion conductive solid electrolyte tube, a cathode lid and an anode lid are thermo-pressure bonded to this α-alumina ring, and welded to the anode lid, the solid electrolyte A sodium-sulfur battery comprising: a battery case that covers a tube from below to form an anode chamber in a gap with the solid electrolyte tube; and a cathode cover that is welded to the cathode cover to form a cathode chamber within the solid electrolyte tube. , a cylindrical metal fiber consisting of at least two layers is arranged in the cathode chamber, a convex part is provided on the upper surface of the α-alumina ring, an anode cover is thermo-pressure bonded to the outside of the convex part, and the anode The lid and the battery case are welded together via the anode auxiliary lid, and a cathode lid is heat-pressure bonded to the inside of the convex portion, and a cathode terminal provided with a through hole is welded to the cathode lid, and a cathode terminal provided with a through hole is welded to the through hole. A sodium-sulfur battery characterized in that a cathode current collector having a groove is inserted into the cathode current collector, and the other end of the cathode current collector is inserted into the metal fiber cylinder to seal a cathode chamber. (2) A cylindrical part is formed in the upper part of the through hole of the cathode terminal, and a cathode terminal cover having a concave cross section is fitted or screwed onto the cylindrical part to seal the cathode chamber. Sodium-sulfur battery as described in section. (3) A metal that is molten at the battery operating temperature is arranged in the concave portion of the cathode terminal cover, and an extension member is provided for extending the cathode terminal through the metal. Sodium-sulfur battery.