JPH0577157B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a sodium-sulfur battery in which eccentricity of a solid electrolyte tube with respect to an anode container is improved.

(Conventional technology) In recent years, secondary batteries for electric vehicles and nighttime power storage have been actively developed, and sodium-sulfur batteries are particularly important because of their superior performance and economy. . In other words, in terms of performance, the theoretical energy density is higher than that of lead-acid batteries, there are no side reactions such as generation of hydrogen or oxygen during charging and discharging, the utilization rate of active materials is high, and in terms of economy, sodium and sulfur are inexpensive. It has the characteristic of being

Such a sodium-sulfur battery consists of molten ions at the anode, molten metal sodium at the cathode, and a solid electrolyte tube made of β-alumina that isolates the two and is selectively permeable to sodium ions. As a result of this reaction, sodium ions pass through the solid electrolyte and react with sulfur at the anode, producing sodium polysulfide.

2Na＋XS→Na ₂ Sx Also, during charging, the opposite reaction occurs to that during discharging.
Sodium and sulfur are produced.

As shown in FIG. 9, the structure of the sodium-sulfur battery is as follows: 1 is an anode terminal, 2 is a cylindrical anode container erected at the upper end of the anode terminal 1, and 3 is the upper end of the cylindrical anode container 2. 4 is a cylindrical solid electrolyte tube made of β alumina that is fixed to the inner end of the insulating plate 3 and forms a cylindrical bag tube extending downward; It has the function of transmitting the active substance sodium as ions.

5 is a cylindrical reservoir (cathode container) fixed to the upper end of the insulating plate 3; 6 is the reservoir 5;
An elongated cathode tube fixed to the center of the upper lid of the tube and extending through the reservoir 5 to the bottom of the cylindrical solid electrolyte tube 4 also serves as a cathode terminal.

7 is a conductive material for the anode, such as carbon mat containing sulfur, which is an anode active substance, and 8 is a stainless steel wick impregnated with molten sodium, which is a cathode active substance.

In the above conventional sodium-sulfur battery, the cylindrical anode container 2 is integrally molded without being divided, and the solid electrolyte tube 4
Nothing was interposed between the lower part of the cylindrical anode container 2 and the bottom of the cylindrical anode container 2.

(Problems to be Solved by the Invention) In the manufacturing process of the conventional sodium-sulfur battery described above, when the insulating plate 3 to which the solid electrolyte tube 4 is fixed to the inner periphery is joined to the cylindrical anode container 2, the solid electrolyte When the electrolyte tube 4 or the cylindrical anode container 2 is bent or otherwise deformed, eccentricity may occur between the solid electrolyte tube 4 and the cylindrical anode container 2.

Therefore, in extreme cases, the solid electrolyte tube 4 becomes eccentric with respect to the anode container 2, as shown in FIG.
The thickness of the conductive material 7 for the anode is no longer uniform all over the top and bottom, and sulfur, which is a cathode active substance, is not used in the thick part 7B in FIG. 10, and sulfur is used early in the thin part 7A. If the solid electrolyte tube 4 is completely depleted, the discharge characteristics of the battery will deteriorate as a whole, and if a thermal cycle is applied due to temperature rise and fall during battery rest, periodic inspection, or when replacing an abnormal battery, the solid electrolyte tube 4 There was a problem in that the solid electrolyte tube 4 was damaged due to bending stress.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention has a cylindrical anode container fixed to an insulating plate fixed to the outer periphery of the upper end of the solid electrolyte tube. It is divided into two parts, an upper anode cylinder and a lower anode cylinder, and a flexible joint part is provided in the frozen part to freely adjust the axial joint angle and fix the upper anode cylinder and the lower anode cylinder in an appropriate positional relationship. (hereinafter referred to as the first invention), or in addition thereto, an axial center holding means is provided between the lower part of the solid electrolyte tube and the bottom of the anode container (hereinafter referred to as the second invention).

(Function) By adopting the above configuration, eccentricity between the solid electrolyte tube and the lower anode tube can be eliminated,
The thickness of the conductive material for the anode can be made uniform over the entire upper and lower portions.

(Example) An example embodying the first invention and the second invention will be described below with reference to FIGS. 1 and 2.

In this embodiment, as shown in FIG. 1, the anode container is divided into an upper anode tube 2a and a lower anode tube 2b, and the lower end of the upper anode tube 2a and the upper end of the lower anode tube 2b are connected by welding. An arcuate flexible joint portion 2c is provided. The adjustable joint 2c can be freely adjusted to any angle like a joint.

The arc-shaped flexible joint 2c is the upper anode tube 2a.
The lower end of the lower anode tube 2b is placed on the outside, and the upper end of the lower anode tube 2b is placed on the inside.

Further, an axial center holding member 9 for holding the axial center of the solid electrolyte tube 4 is provided on the bottom surface of the lower anode tube 2b. As shown in FIG. 2, the coaxial center holding member 9 forms a wrapper-shaped ring that fits into the lower spherical portion of the solid electrolyte tube 4.

The structure of the sodium-sulfur battery other than the above is similar to the structure of the conventional sodium-sulfur battery described above.

Next, the operation of the above embodiment will be explained.

When manufacturing a sodium-sulfur battery, the insulating plate 3 to which the solid electrolyte tube 4 is fixed to the inner circumference is first joined to the upper anode tube 2a, and then the upper anode tube 2a is
is welded to the lower anode tube 2b at the universal joint 2c.

In this case, the flexible joint portion 2c has an arcuate cross section (constituting a part of a spherical surface as a whole), and the joining angle can be freely adjusted, so that the cylindrical portion of the lower anode tube 2b and the cylindrical portion of the solid electrolyte tube 4 By setting the distance between the solid electrolyte tube 4 or the lower anode tube 2b at a position that maintains a constant distance over the entire circumference, and joining the flexible joint 2c at that position, even if the solid electrolyte tube 4 or the lower anode tube 2b is bent or otherwise deformed, Eccentricity between the solid electrolyte tube 4 and the lower anode tube 2b can be almost eliminated.

Further, an axis center holding member 9 in the form of a lug-like ring as shown in FIG. 2 is attached to the bottom surface of the lower anode tube 2b, and the upper anode tube 2a and the lower anode tube 2b are adjusted by the flexible joint 2c. In this case, the solid electrolyte tube 4 is supported by the axial center holding member 9, and the solid electrolyte tube 4 can be smoothly set at the center position, that is, at the correct axial center with respect to the lower anode tube 2b.

Therefore, since the conductive material 7 for the anode inserted between the lower anode tube 2b and the solid electrolyte tube 4 has a constant thickness from top to bottom, the sulfur as the anode active substance is uniformly mixed with sodium throughout. It takes part in the reaction, has a high utilization rate, and improves the discharge characteristics of the battery.

Furthermore, since eccentricity between the solid electrolyte tube 4 and the anode container is prevented, even if the solid electrolyte tube 4 is subjected to a thermal cycle based on temperature rise and fall of the battery, both the anode tubes 4 and
The thickness of the anode formed between a, 2b and the solid electrolyte tube 4 is uniform, and bending stress is not applied to the solid electrolyte tube 4, so that it will not be damaged.

The first invention and the second invention are not limited to the above-mentioned embodiments, but can also be configured as follows.

(1) As the axial center holding means for the solid electrolyte tube 4, the axial center holding member 9 in the form of a conical ring was used in the above embodiment, but instead of this, a conical axial center holding member as shown in FIG. 9a or a dish-shaped shaft center holding member 9b as shown in FIG. 4 can be used.

Such a conical or dish-shaped shaft center holding member 9
Even if a or 9b is used, the same effect as that of the shaft-center holding member 9 of the rattle-shaped ring can be obtained.

(2) As a means for holding the axis of the solid electrolyte tube 4, an engaging protrusion is provided at the lower end of the solid electrolyte tube 4 as shown in FIG. It is also possible to use an uneven shaft center holding member 9c provided with matching recesses.

In this case, it is also possible to use the engagement convex portion at the lower end of the solid electrolyte tube 4 as an engagement concave portion, and the engagement concave portion on the bottom surface of the lower anode tube 2b to serve as an engagement convex portion.

(3) In the above embodiment, the flexible joint 2c has the lower end of the upper anode tube 2a facing outward, and the lower end of the lower anode tube 2b facing outward.
However, as shown in FIG. 6, on the contrary, the lower end of the upper anode tube 2a is inwardly overlapped with the lower anode tube 2b.
There is no problem even if the upper end portion of the material is configured to overlap outwardly.

(4) In the above embodiment, the shaft center holding member 9 in the shape of a rattle ring was used to hold the shaft center of the solid electrolyte tube 4, but as shown in FIG. 7, this is used in the first invention. It is not necessary to do so, and the purpose can be achieved using only the universal joint 2c.

In addition, when performing further flexible joining, see Figure 8a.
With the structure shown in (b) and (b), assembly can be easily performed.

That is, if the diameter of the tip section of the container joint located on the outside is the maximum diameter, as shown in A in FIG. 8a and B in FIG. 8b, the upper anode tube 2a and the lower anode tube 2b Easy to join.

In addition, in order to obtain the above-mentioned action and effect, it is also possible to employ only an axial center holding means between the lower part of the solid electrolyte tube 4 and the bottom of the lower anode tube 2b, and each of the above-mentioned means can be used as the coaxial center holding means. can be implemented as is.

Effects of the Invention In the sodium-sulfur battery of the present invention, the angle of the joint is adjusted to fix the upper anode tube and the lower anode tube in an appropriate positional relationship, and then the flexible joint is joined. Since eccentricity between the solid electrolyte tube and the anode container is prevented, the thickness of the conductive material for the anode can be kept constant across the top and bottom, and the discharge characteristics of the battery can be improved without reducing the utilization rate of sulfur, which is an anode active material. You can improve your performance.

[Brief explanation of the drawing]

Figure 1 shows an embodiment of the present invention.
A vertical cross-sectional view of a main part of a sulfur battery, FIG. 2 is a perspective view showing a ratchet-shaped ring axis center holding member, and FIGS. 3 to 7 are longitudinal cross-sectional views of a main part of a sodium-sulfur battery showing other examples of the present invention. , Figures 8a and b are partial cross-sectional views showing the joint between the upper anode tube and the lower anode tube, Figure 9 is a longitudinal cross-sectional view of a conventional sodium-sulfur battery, and Figure 10 is an extreme cross-sectional view of a conventional solid electrolyte tube. FIG. 2a... Upper anode tube, 2b... Lower anode tube, 2
c...Universal joint, 3...Insulating plate, 4...Solid electrolyte tube.

Claims (1)

[Claims] 1. Cylindrical anode containers 2a, 2b fixed to an insulating plate 3 fixed to the outer periphery of the upper end of the solid electrolyte tube 4
is divided into two parts, an upper anode cylinder 2a and a lower anode cylinder 2b, at the upper part, and the axial joining angle at the connection part is freely adjustable, so that the upper anode cylinder 2a and the lower anode cylinder 2b are placed in an appropriate positional relationship. Flexible joint 2 to fix
A sodium-sulfur battery characterized by providing c. 2. The flexible joint 2c is such that the lower end of the upper anode cylinder 2a is superimposed on the outside of the upper end of the lower anode cylinder 2b, or the lower end of the upper anode cylinder 2a is connected to the lower anode cylinder 2b.
The sodium-sulfur battery according to claim 1, wherein the sodium-sulfur battery is polymerized inside b. 3 Cylindrical anode containers 2a and 2b fixed to the insulating plate 3 fixed to the outer periphery of the upper end of the solid electrolyte tube 4
is divided into two parts, an upper anode cylinder 2a and a lower anode cylinder 2b, at the upper part, and the axial joining angle at the connection part is freely adjustable, so that the upper anode cylinder 2a and the lower anode cylinder 2b are placed in an appropriate positional relationship. Flexible joint 2 to fix
c, and an axial center holding means is provided between the lower part of the solid electrolyte tube 4 and the bottom of the lower anode tube 2b. 4. The sodium-sulfur battery according to claim 3, wherein the axial center holding means is a lapel-shaped ring provided at the bottom of the lower anode tube 2b and adapted to the lower spherical portion of the solid electrolyte tube 4. 5. The axial center holding means is provided at the bottom of the lower anode tube 2b and is a conical or dish-shaped axial center holding means adapted to the lower spherical part of the solid electrolyte tube 4. Sodium-sulfur battery. 6 The axial center holding means consists of an engaging protrusion or recess protruding from or attached to the lower end of the solid electrolyte tube 4 and the lower anode tube 2.
The sodium-sulfur battery according to claim 3, wherein the engaging convex portion or concave portion provided at the bottom of the portion b is an engaging concave portion or convex portion to be engaged. 7. The flexible joint 2c is such that the lower end of the upper anode tube 2a is superimposed on the outside of the upper end of the lower anode tube 2b, or the lower end of the upper anode tube 2a is connected to the lower anode tube 2b.
The sodium-sulfur battery according to claim 3, wherein the sodium-sulfur battery is polymerized inside b.