JP2633333B2 - Sodium-sulfur battery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sodium-sulfur battery, and more particularly, to a sodium-sulfur battery using plate-like beta alumina as a solid electrolyte.

[Prior art] A sodium-sulfur battery has molten metal sodium as a cathode active material on one side and molten sulfur as an anode active material on the other side, and both have selective permeability to sodium ions. Isolate with beta alumina solid electrolyte, 300-3
This is a high-temperature secondary battery operated at 50 ° C.

As such a sodium-sulfur battery, for example, the one shown in FIG. 7 is conventionally known. That is,
A cylindrical anode metal container 2 containing an anode conductive material 1 such as carbon felt impregnated with molten sulfur S as an anode active material; an upper end of the anode metal container 2 and an insulator ring 3 made of, for example, alpha alumina; And a cathode metal container 4 for storing molten sodium metal sodium, which is joined to the inner periphery of the insulator ring 3 and
It has a bottomed cylindrical beta alumina tube 5 having a function of selectively transmitting Na ⁺ . A cathode tube 7 extending downward through the cathode metal container 4 to a position near the bottom of the beta-alumina tube 5 is supported through the center of the upper lid 6 of the cathode metal container 4.

An example in which plate-like beta alumina is used in a sodium-sulfur battery is described in JP-A-49-105134.

In the sodium-sulfur battery having the above configuration,
During discharge, the molten metal sodium emits electrons to become sodium ions, which pass through the beta-alumina solid electrolyte and move to the anode side, where the sulfur in the anode reacts with the electrons that have passed through the external circuit to react with sodium polysulfide. Produces
Generates a voltage of about 2V. On the other hand, at the time of charging, a reaction of generating sodium and sulfur occurs contrary to the discharging.

[Problems to be Solved by the Invention] However, in the sodium-sulfur battery having the above-described configuration, when cylindrical beta-alumina with a bottom is used, there are restrictions on the thickness or size of the beta-alumina in terms of manufacturing. And one cylindrical beta alumina with bottom
The method of storing the solid electrolyte in the container one by one has a disadvantage that the area of the solid electrolyte cannot be increased with respect to the volume or weight of the battery, and the battery efficiency cannot be increased. Further, those using the plate-like beta-alumina do not refer to the joining method of the plate-like beta-alumina and the container for the anode active material and the container for the cathode active material, which are important technical issues, and are not described in Examples. However, as shown, there was a problem in long-term reliability as a battery.

Means for Solving the Problems The inventors of the present invention have conducted various studies to solve the above-mentioned problems of the conventional battery structure. As a result, the beta-alumina solid electrolyte was formed into a plate shape and joined to a metal container. The present inventors have found that the conventional problem can be solved by using a sodium-sulfur battery whose surface is devised, and have completed the present invention.

That is, according to the present invention, a sodium-sulfur battery using plate-like beta-alumina as a solid electrolyte, wherein the plate-like beta-alumina is placed in a storage container for an anode active material and a storage container for a cathode active material via a sealing material. Sodium characterized by forming an anode chamber and a cathode chamber isolated on both sides of a plate-like beta alumina by bonding hermetically with an adhesive, and storing an anode active material in the anode chamber and a cathode active material in the cathode chamber. A sulfur battery is provided.

Further, in a sodium-sulfur battery using plate-like beta-alumina, a metal plate is provided between the plate-like beta-alumina and the container for the anode active material and the container for the cathode active material over the entire length of the plate-like beta-alumina. When the beta alumina plate is protected by this, it is possible to prevent the beta alumina plate from being damaged by thermal stress or the like.

Further, according to the present invention, there is provided a sodium-sulfur battery configured by connecting a plate-like beta-alumina solid electrolyte and a storage container for the anode active material and a storage container for the cathode active material by a metal plate, A sodium-sulfur battery is provided in which a joint between alumina and a metal plate is separated from a joint between the storage container for the anode active material and the storage container for the cathode active material and the metal plate.

Furthermore, the metal plate joined to each of the plate-like beta-alumina, the container for storing the anode active material, and the container for storing the cathode active material has a bellows shape in the middle part of each joint, so that the container between the container and the beta-alumina The acting thermal stress and the stress transmitted to the beta alumina from the outside can be absorbed, and resistance to breakage increases.

In the present invention, when the plate-like beta alumina is provided with irregularities (including a wavy structure), the surface area increases, the amount of sodium ions permeated increases, and at the same time, it is added from the storage container for the anode active material and the storage container for the cathode active material. It is preferable because the external force is absorbed by the entire beta-alumina plate, so that resistance to breakage increases.

Further, as described above, when a metal plate is provided over the entire length of the plate-shaped beta alumina, if a depression is provided in the metal plate so that the metal plate comes into contact with the beta alumina plate, a part of the beta alumina plate may be damaged. Thus, even if a situation occurs in which the positive and negative electrode active materials come into direct contact with each other, the reaction amount of the positive and negative electrode active materials can be suppressed to a small amount, and damage can be minimized.

[Operation] In the present invention, a battery is formed by using plate-like beta alumina as a solid electrolyte, arranging a sealing material on both sides of beta alumina, and joining the anode active material storage container and the cathode active material storage container. High resistance to joint stress caused by environmental temperature change between battery operation (high temperature of 300-350 ° C) and shutdown (room temperature), causing breakage and damage at the joint There is little fear.

That is, thermal stress caused by a difference in physical properties (coefficient of thermal expansion, Young's modulus, Poisson's ratio, etc.) between the storage container and beta-alumina is relaxed. A non-uniform thermal stress generated in the beta-alumina is relieved by inserting a sealing material having a buffer effect and symmetrically disposing the sealing material on both sides of the end of the beta-alumina.

In addition, as the above-mentioned sealing material, a metal such as stainless steel, nickel, cobalt, iron, iron-chromium alloy, titanium, chromium, and magnesia, zirconia, alumina, beryllia, boride, etc., which can sufficiently achieve the sealing of the joint portion are provided. Ceramics such as titanium can be used, but those having an intermediate thermal expansion coefficient between those of beta-alumina and the container for the anode active material and the container for the cathode active material are preferable for relaxing the stress at the joint.

Further, as the material of the storage container of the anode active material and the storage container of the cathode active material, a metal material is usually used,
The present invention is not limited to this, and ceramics such as magnesia, zirconia, and alumina can be used.

Further, a sodium-sulfur battery configured by connecting a plate-like beta-alumina solid electrolyte, a storage container for the anode active material, and a storage container for the cathode active material by a metal plate,
In a sodium-sulfur battery in which the joint between the plate-like beta alumina and the metal plate and the joint between the storage container for the anode active material and the storage container for the cathode active material and the metal plate are separated, during operation and during shutdown, Even if a stress is generated at the joint portion due to a difference in thermal expansion coefficient of each member due to a temperature change and a displacement occurs, the metal plate absorbs and relaxes the displacement, thereby avoiding breakage and damage. And when this metal plate has a bellows shape in the middle part of each joint, further destruction,
Great effect of avoiding damage.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to the illustrated examples, but the present invention is not limited to these examples.

FIG. 1 is an explanatory sectional view showing a basic embodiment of the structure of a sodium-sulfur battery of the present invention. A cathode metal container 12 and an anode are provided on both sides of a plate-like beta alumina solid electrolyte 10 with an adhesive via a sealing material 11. A metal container 13 is joined, and a cathode active material 14 and an anode active material 15 are contained in each container.

FIG. 2 is an explanatory sectional view showing another embodiment of the configuration of the sodium-sulfur battery of the present invention, in which a plurality of plate-like beta alumina solid electrolytes 10 are provided.

FIG. 3 is an explanatory sectional view showing still another embodiment of the configuration of the sodium-sulfur battery of the present invention, in which the surface area is increased by making the plate-like beta alumina solid electrolyte 10 wavy. In this case, since the surface area of the solid electrolyte 10 increases, the amount of sodium ions per unit volume increases,
Battery performance is improved.

FIGS. 4 and 5 show an embodiment in which metal plates 16 are joined to both sides of the plate-like beta-alumina solid electrolyte 10.
To improve the sealing property between the cathode metal container 12 and the anode metal container 13, and divide the inside of the cathode metal container 12 and the inside of the anode metal container 13 into a plurality, and accommodate each of the anode active material and the cathode active material. It is intended to provide a plurality of anode chambers and cathode chambers. Here, in FIG.
Shows a case where more anode chambers and cathode chambers are provided as an uneven structure.

When configured as shown in FIG. 4, the metal plate 16 bonded to both ends of the plate-like beta-alumina absorbs and protects stress applied from the outside, so that destruction and damage can be prevented.
The battery efficiency can be improved by making the plate-like beta alumina thin.

Further, with the configuration shown in FIG. 5, even if a part of the plate-like beta-alumina is damaged and a situation in which the anode active material and the cathode active material come into direct contact occurs, the anode active material and the cathode active material can be used. Can be suppressed to a small amount, and damage can be minimized.

FIG. 6 shows an embodiment in which the beta-alumina solid electrolyte 10 and the cathode metal container 12 and the anode metal container 13 are connected by an intermediate metal plate 17 having a bellows shape. In the case of this example, Even if a stress is generated at the joint due to a difference in thermal expansion coefficient between the members due to a temperature change between the operation and the stop, and displacement occurs, the intermediate metal plate 17 having a bellows shape absorbs and moderates the displacement. Therefore, destruction and damage at the joint can be avoided, which is a particularly preferable structure.
The intermediate metal plate 17 and the solid electrolyte 10 and the intermediate metal plate 17 and the cathode metal container 12 and the anode metal container 13 are joined by an inorganic glass 18.

In the above embodiment, the metal plate 16 or the intermediate metal plate 17
Although there is no particular limitation on the material of aluminum, aluminum, aluminum alloy, stainless steel, nickel, cobalt, iron,
Iron-chromium alloy, titanium, chrome, etc. can be used.

 Next, more specific implementation results of the present invention will be described.

(Example 1) As a solid electrolyte, a plate-shaped beta alumina having a square shape of 100 mm and a thickness of 2 mm was used. The storage container for the anode active material and the storage container for the cathode active material are made of a 1 mm thick metal plate, the adhesive width with beta alumina is 10 mm, and the thickness of the storage section for the anode active material and the cathode active material is 10 mm. It was constituted so that it might become.

Tables 1 and 2 show the materials of the storage container, sealant and adhesive.
And Table 3. Table 4 shows these combinations and the evaluation test results of the battery cells formed by the combination. Here, the result of the mark in the appearance state is
After bonding, apply the staining solution to the bonded part and observe it with the naked eye,
It shows good test results without cracks and the like. The results of the crosses indicate that abnormalities such as cracks were observed in the bonded part or beta alumina.
Put the battery cell in a thermostat heated to 110 ° C, hold it for 1 hour, and then quickly put it in a water tank adjusted to 20 ° C.
Thereafter, a staining solution was applied, and the occurrence of cracks and the like was observed.
The contents of the results of the marks ○ and × are the same as the appearance.
If there is no problem in the cooling test with a difference of 90 ° C, there should be no problem under the actual operating conditions, for example, under the heating or cooling conditions at the start or stop of the operation, and there should be excellent resistance to the cooling cycle. Has been confirmed.

From these results, when the beta alumina is joined to the storage container for the anode active material and the storage container for the cathode active material, a sealing material is used between the beta alumina and the storage container, and
The battery cell constituted by arranging and joining them on both sides of beta alumina has a good adhesion state, and even in a cooling test with a difference of 90 ° C., there is no problem such as occurrence of cracks, and a good It was a result.

On the other hand, in the case of bonding by a method other than the present invention, which was carried out for comparison, there were problems such as a poor bonding state or cracking in a thermal test.

(Example 2) As a solid electrolyte, plate-shaped beta alumina having a square shape of 100 mm and a thickness of 1 mm was used. Sample No. 12 was a flat plate. Sample N
In the case of o.13, a 10-mm end of the beta alumina was used as an adhesion allowance, and corrugations were provided at the center (80 × 80 mm) so that the radius of curvature of the convex portion was 3 mm and the radius of curvature of the concave portion was 2 mm. For sample No. 14, the edge of the beta-alumina 10 mm was similarly used as the bonding margin, and the center (80
× 80 mm), concavities and convexities in which the radius of curvature of the convex portion was 3 mm and the radius of curvature of the concave portion was 2 mm were provided concentrically.

The surface area of the beta alumina except the end 10mm of adhesion margins sample No.13 is 10000mm whereas sample No.12 is 6400Mm ^2
2 , when sample No. 14 was 8600 mm ² and sample No. 12 was 100, sample No. 13 was 156 and sample No. 14 was 135.

The storage container was made of aluminum (M1) on the anode side and stainless steel (M3) on the cathode side.

The sealing material was iron and chromium alloy (M7) for both the positive and negative electrodes.

The adhesive was borosilicate glass (S2) for both the positive and negative electrodes.

Then, each member was adhered using the end portion 10 mm of the beta alumina plate as an adhering margin to prepare a battery cell.

Sample No. 12 was obtained by storing sulfur in the anode side container and metallic sodium in the cathode side container and heating it to 350 ° C.
On the other hand, sample No. 13 and sample No. 14
An increase in current corresponding to 30% was observed.

(Example 3) As a solid electrolyte, a plate-shaped beta alumina having a square of 100 mm and a thickness of 0.8 mm was used, and an end portion of the beta alumina of 10 mm was used as a bonding margin.

The storage container for the anode active material and the storage container for the cathode active material were aluminum (M1).

The sealing material was stainless steel (M3), and the stainless steel plate was also used as a metal plate extending over both sides of beta alumina. In sample No. 15, the metal plate was a flat plate parallel to beta-alumina (FIG. 4), and in sample No. 16, a recess was provided every 20 mm to make contact with beta-alumina (FIG. 5).

These were adhered using an adhesive (S2) to form a battery cell. The state of the joint after bonding was good for all samples, and no problems such as cracks occurred in the 90 ° C. differential cooling / heating test. For comparison, 100
℃, 110 ℃ and 120 ℃ difference between the thermal test
In sample No. 15, beta alumina was broken at a difference of 120 ° C., whereas in sample No. 16, there was no problem that breakage or damage occurred even at a difference of 120 ° C.

Furthermore, there was no problem that beta-alumina was damaged in a thermal test in which the battery cell was heated to 350 ° C. and cooled to room temperature, and the battery operated well.

In sample No. 16, even if a part of the beta alumina was damaged and the anode active material and the cathode active material were in direct contact with each other, the amount of reaction between the anode active material and the cathode active material was small. And damage can be minimized.

(Example 4) As a solid electrolyte, a plate-shaped beta alumina having a square shape of 100 mm and a thickness of 1 mm was used, and an end portion of 5 mm of the beta alumina was used as a bonding margin.

The storage container for the anode active material and the storage container for the cathode active material were made of stainless steel (M3). The intermediate metal plate is stainless steel (M
3) and 90mm inside so that 120mm square and 15mm width
A square hollow was provided. Beta-alumina and the intermediate metal plate were bonded together with a bonding margin of 5 mm, and the storage container for the anode active material and the storage container for the cathode active material and the intermediate metal plate were bonded together with a bonding margin of 5 mm.

For sample No. 17, the intermediate metal plate was a flat plate, and for sample No. 18,
As shown in the drawing, a central portion having a width of 15 mm was provided with a concave bellows shape having a radius of curvature of 5 mm.

The bonding condition after bonding was good for all samples, 90
There was no problem that the beta alumina was broken in the temperature difference cooling test. 100 ° C, 110 ° C and 12 for comparison
When a thermal test with a difference of 0 ° C was performed, the temperature of sample No. 17 was 110 ° C.
Sample No. 18
There was no problem that breakage occurred even at 120 ° C difference.

Further, in a cooling test in which the battery cell was heated to 350 ° C. and cooled to room temperature, there was no problem that the beta alumina was damaged, and the battery operated well.

It should be noted that the present invention is not limited to the above embodiments, and it has been confirmed that almost the same results as those of each embodiment can be obtained for combinations other than the embodiments described in Tables 1 to 3. Was.

[Effects of the Invention] As described above, the present invention has the following effects.

According to the sodium-sulfur battery of the first aspect, a battery having a large strength and excellent durability can be provided.

According to the sodium-sulfur battery of the second aspect, the permeation amount of sodium ions increases, and the battery performance can be improved.

According to the sodium-sulfur battery according to the third aspect, the metal plate joined to both ends of the beta alumina absorbs and protects the stress applied from the outside, so that destruction and damage can be prevented. This has the effect of improving the battery efficiency.

According to the sodium-sulfur battery of the fourth aspect, since the stress and displacement are absorbed and relaxed by the intermediate metal plate, destruction and damage at the joint can be avoided.

According to the sodium-sulfur battery of the fifth aspect, since the intermediate metal plate has a bellows shape, destruction and damage at the joint can be more reliably avoided.

[Brief description of the drawings]

1 to 6 are sectional explanatory views showing an embodiment of a sodium-sulfur battery of the present invention, and FIG. 7 is a conventional sodium-sulfur battery.
FIG. 2 is a schematic cross-sectional view illustrating a configuration example of a sulfur battery. 10: plate-like beta alumina solid electrolyte, 11: sealing material, 12: cathode metal container, 13: anode metal container, 14 ...
Cathode active material, 15 Anode active material, 16 Metal plate, 17
Intermediate metal plate, 18 ... Inorganic glass.

Claims (5)

(57) [Claims] 1. A sodium-sulfur battery using plate-like beta-alumina as a solid electrolyte, wherein said plate-like beta-alumina is attached to a storage container for an anode active material and a storage container for a cathode active material via an adhesive via a sealing material. A sodium-sulfur battery characterized by forming an anode chamber and a cathode chamber separated from each other on both sides of a plate-like beta-alumina by hermetically bonding, and storing an anode active material in the anode chamber and a cathode active material in the cathode chamber. . 2. The sodium-sulfur battery according to claim 1, wherein the plate-like beta alumina has irregularities. 3. A metal plate is provided over the entire length of the plate-like beta alumina, between the plate-like beta alumina and the container for storing the anode active material, and between the plate-like beta alumina and the container for storing the cathode active material. 2. The sodium-sulfur battery according to 1. 4. A sodium-sulfur battery comprising a plate-like beta-alumina solid electrolyte and a container for storing an anode active material, and a plate-like beta-alumina and a container for storing a cathode active material connected by a metal plate, A sodium-sulfur battery in which a joint between the plate-like beta alumina and the metal plate is separated from a joint between the container for the anode active material and the container for the cathode active material and the metal plate. 5. The sodium-containing metal oxide according to claim 4, wherein the metal plate joined to each of the plate-like beta-alumina, the container for storing the anode active material and the container for storing the cathode active material has a bellows shape at an intermediate portion of each joint. Sulfur battery.