JP2000231932A - Method for assembling sodium-sulfer battery and positive electrode metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for assembling a sodium-sulfer battery with small loads on workers and high productivity. SOLUTION: This positive electrode metal 5 has an upper side flange part that is glass-joined to the upper periphery of a solid electrolyte tube 13 and extends in the outer direction from a cylindrical part and the upper end thereof, a lower side flange part extending from the under end thereof in the inner direction and a rib disposed under the upper side flange. The upper face of the lower side flange part is thermo compression bonded to the lower end face of an insulating ring 3, the lower face of the flange part of a negative electrode metal 7 having a flange part extending from a cylindrical part and the periphery thereof in the outer direction is thermo compression bonded to the upper end face of the insulating ring 3 and then a joined body 1 is made. A sodium azide and a positive electrode mold 11 are housed in a cylindrical positive electrode container main body 9a, a bottom cover 9b is welded and fixed to one opening of the positive electrode container main body 9a, the other opening is turned upward, the joined body 1 is fit and then a contact interface S1 is welded and sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for assembling a sodium-sulfur battery and an anode fitting used for the method.

[0002]

2. Description of the Related 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. This is a high-temperature secondary battery operated at 300 to 350 ° C. isolated by a β-alumina solid electrolyte.

As an example of such a sodium-sulfur battery, one having a structure as shown in FIG. 6 is known.
In the figure, reference numeral 13 denotes a bottomed cylindrical solid electrolyte tube made of β-alumina, which is an anode container formed by welding and fixing a bottom lid 9b to one opening of a cylindrical anode container body 9a having a constriction 10. 9, the solid electrolyte tube 13
Anode chamber R ₂ is formed on the outside of. The anode chamber R _2,
An anode mold 11 in which an anode conductive material such as a carbon mat is impregnated with sulfur S as an anode active material is accommodated. On the other hand, inside the solid electrolyte tube 13, a cathode chamber R _{1 is provided.}
Is formed, and molten metal sodium Na is used as a cathode active material.
Is disposed.

The anode container 9 and the solid electrolyte tube 13 have α
The upper opening of the insulating ring 3 is connected to a cathode metal fitting 7 through an alumina insulating ring 3 and an anode metal fitting 5;
Through the cathode lid 19. Anode compartment R ₂
Upper space and the cartridge 15 which is arranged to the cathode chamber R ₁ of
The headspace, nitrogen gas is enclosed, the by nitrogen gas, and the pressure in the pressure and the cathode chamber R ₁ in the anode chamber R ₂ is maintained in a predetermined range suitable for charging and discharging, respectively.

In the sodium-sulfur battery having such a structure, at the time of discharge, sodium Na flowing out of the passage hole 17 formed in the bottom of the cartridge 15 is guided to the gap between the cartridge 15 and the solid electrolyte tube 13. sodium Na becomes sodium ions to release electrons in passes through the solid electrolyte tube 13 moves to the anode chamber R _2, electrons and react with polysulfide having passed through the sulfur S and the external circuit of the anode chamber R ₂ Generates sodium and generates voltage. At the time of charging, a reaction of forming sodium Na and sulfur S occurs in reverse to the discharging.

[0006] Conventionally, sodium-
In assembling a sulfur battery, first, a joined body of an insulating ring, a solid electrolyte tube, an anode fitting, and a cathode fitting is prepared. As shown in FIG. 7, the joined body 1 is a solid electrolyte tube 1 having a bottomed cylindrical shape at a lower portion of the inner peripheral surface of an insulating ring 3.
The upper part of the outer peripheral surface of 3 is glass-bonded. Anode fitting 5
Has a cylindrical portion 5a, an upper flange portion 5b extending outward from the upper end of the cylindrical portion 5a, and a lower flange portion 5c extending inward from the lower end of the cylindrical portion 5a. Are joined to the lower end surface of the insulating ring 3 by heat and pressure. The cathode fitting 7 has a cylindrical portion 7a and a flange portion 7b projecting outward from the outer periphery of the cylindrical portion 7a.
And the lower surface of the flange portion 7b is hot-press bonded to the upper end surface of the insulating ring 3.

After manufacturing such a joined body 1, FIG.
Anode container body 9 to which the bottom lid has not yet been joined
a, the joint 1 is inserted into the upper opening.
The fitted, welding the contact interface S ₁ of the joint body 1 anode fitting 5 and the anode container body 9a from the outside. At the time of this welding, the solid electrolyte tube 1 inserted into the anode container body 9a
An eccentricity correction jig (not shown) is disposed in the anode container body 9a to center the solid electrolyte tube 13 in order to prevent welding from being performed in a state where 3 is eccentric.

After attaching the joined body 1 to the anode container body 9a in this way, the eccentricity correcting jig is removed from the inside of the anode container body 9a and inverted as shown in FIG. Then, the anode mold 11 is accommodated in the anode container main body 9a, and the air inside the anode container main body 9a is exhausted under a reduced pressure atmosphere to make the inside of the anode container main body 9a a vacuum state.
b, the contact interface S between the bottom lid 9b and the anode container body 9a
₂ is sealed and welded. Incidentally, the anode chamber R _2, the gas generating device consisting of sodium azide with the anode mold 11 has been housed, the nitrogen gas generated Sodium This azide When the battery is operating temperatures is vaporized by thermal decomposition,
Raising the pressure in the anode chamber R ₂ to a predetermined pressure.

[0009]

By the way, recently, the size of the sodium-sulfur battery is increasing, and in the largest sodium-sulfur battery at present, the joined body 1 is welded to the anode container body 9a as shown in FIG. When the weight is 5
It can be as much as kg. In assembling such a large and heavy sodium-sulfur battery, it is burdensome for the operator to reverse the joint 1 after welding the joint 1 to the anode container body 9a as in the prior art, as shown in FIG. The presence of the reversing step has been a factor that impairs battery productivity.

[0010] The present invention has been made in view of such conventional circumstances. Even when assembling a large sodium-sulfur battery, a large burden is not imposed on an operator, and high productivity can be obtained. An object of the present invention is to provide a method for assembling such a sodium-sulfur battery. Another object of the present invention is to provide an anode fitting that can be suitably used in such an assembling method.

[0011]

According to the present invention, an upper portion of an outer peripheral surface of a solid electrolyte tube having a bottomed cylindrical shape is glass-bonded to a lower portion of an inner peripheral surface of an insulating ring. The lower flange portion of the anode fitting having an upper flange portion extending outward from an upper end, a lower flange portion extending inward from a lower end of the cylindrical portion, and a rib provided below the upper flange portion. The upper surface is placed on the lower end surface of the insulating ring, and the lower surface of the flange portion of the cathode fitting having a cylindrical portion and a flange portion projecting outward from the outer periphery of the cylindrical portion is placed on the upper end surface of the insulating ring. A pressure-bonded joined body is prepared, the anode mold is previously housed together with sodium azide in a cylindrical anode container body having a constriction, and the bottom lid is welded and fixed to one opening, and then the anode is fixed. Sodium-sulfur, wherein the joint is fitted into the opening with the other opening of the container body facing upward, and the contact interface between the anode container body and the anode fitting is welded and sealed. A method for assembling a battery is provided.

According to the present invention, the cylindrical portion, the upper flange portion projecting outward from the upper end of the cylindrical portion, the lower flange portion projecting inward from the lower end of the cylindrical portion, and the upper flange portion And an anode fitting having a rib provided below.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for assembling a sodium-sulfur battery according to the present invention, first, a joined body of an insulating ring, a solid electrolyte tube, an anode fitting, and a cathode fitting is prepared in the same manner as in the conventional assembling method. As a feature of the present invention, an anode mold 11 is previously stored together with sodium azide (not shown) in a cylindrical anode container main body 9a having a constriction 10 as shown in FIG. An anode container 9 to which an anode container 9b is fixed by welding is prepared, and as shown in FIG. 2, with the other opening of the anode container body 9a facing upward, the insulating ring 3, the solid electrolyte tube 13, Anode fitting 5
And the joined body 1 of the cathode metal fittings 7 are fitted together, and the anode container body 9a is fitted.
The contact interface S ₁ between the anode and the metal fitting 5 is sealed by welding.

That is, in the assembling method of the present invention, as in the prior art, the step of welding the joined body to the anode container main body before the bottom lid and inverting this to fix the bottom lid by welding is performed. Since it does not include it, even when assembling a large and heavy sodium-sulfur battery, a large burden is not imposed on the operator. The reason why the constriction 10 is formed in the anode container main body 9a is to make the anode container 9 have a spring effect by the constriction 10 and absorb and reduce the shrinkage of the anode container 9 due to the thermal change.

Further, in the present invention, as another feature, an anode fitting 5 having a rib 5d as shown in FIG. 3 is used for producing the above-mentioned joined body. FIG. 3A is a side view showing a part in cross section, and FIG. 3B is a plan view seen from below. The anode fitting 5 includes a cylindrical portion 5 a and a cylindrical portion 5.
upper flange portion 5b protruding outward from the upper end of a
And a lower flange portion 5c projecting inward from the lower end of the cylindrical portion 5a, and has a rib 5d provided below the upper flange portion 5b as a configuration not present in the conventional anode fitting. .

In order to fit the joined body into the opening of the anode container main body, some clearance is required between the anode container main body and the anode fitting of the joined body. As described above, in the conventional assembling method, when the joined body is welded to the anode container body, the clearance prevents the solid electrolyte tube inserted into the anode container body from being welded in an eccentric state. Therefore, an eccentricity correction jig is arranged in the anode container body to center the solid electrolyte tube.

However, in the assembling method of the present invention,
Before welding the joined body, the bottom lid is first welded and fixed to the anode container body, so the eccentricity correction jig is placed in the anode container body and the solid electrolyte tube is centered and joined as before. Inability to perform body welding. For this reason, when the assembling method as in the present invention is performed on the joined body manufactured using the conventional anode fitting, the solid electrolyte tube is welded without being sufficiently centered, as shown in FIG. In addition, due to the eccentricity of the solid electrolyte tube 13, when the anode mold 11 existing between the anode container 9 and the solid electrolyte tube 13 is restored by sulfur melting during operation, uneven portions of thin portions and thick portions are formed.

If the thickness of the anode mold 11 after restoration is not uniform as described above, the battery characteristics such as the resistance on the anode side are increased and the charge / discharge efficiency is deteriorated. Generally, the sodium or 70mm diameter - in the sulfur batteries, adversely affect the battery characteristics when exceeding 0.8 mm (distance between the center O ₂ of the center O ₁ and the solid electrolyte tube 13 of the anode container 9) eccentricity E Get out.

Further, after assembling the battery, the battery is maintained at a high temperature, and nitrogen gas is generated from sodium azide housed in the anode chamber R ₂ as a gas generating element to bring the inside of the anode chamber R ₂ to a predetermined pressure. In the anode chamber R ₂ under reduced pressure atmosphere.
In a state in which the air is evacuated of internal, it is necessary to seal the anode chamber R ₂ by welding contact interface S ₁ between the anode container body 9a and the anode metal fitting 5 of the joint body 1 as shown in FIG.

However, in the conventional anode fitting, before and after welding, in a state where the joined body is fitted to the anode vessel main body, the inside and outside of the anode vessel serving as an exhaust passage between the anode metal fitting and the anode vessel main body are formed. Since it is difficult to form a gap communicating with the anode, it is difficult to exhaust air from the anode chamber.

Therefore, in the present invention, in order to solve these problems, a joined body is manufactured using the anode fitting 5 having the ribs 5d formed as shown in FIG. When a joined body manufactured using such an anode fitting is used, even if there is a clearance necessary for fitting between the anode container main body and the anode fitting of the joined body, the anode fitting 5 can be used. Centering can be easily performed by the formed ribs 5d, and the eccentric amount of the solid electrolyte tube can be suppressed to a small value even in the assembling method of the present invention in which an eccentricity correction jig cannot be used.

Further, when the joined body is fitted to the anode container main body before welding, the rib 5 d of the anode metal fitting 5 allows communication between the anode metal fitting and the anode container main body from the inside of the anode container to the outside. a gap, the gap can be easily performed exhaust air becomes a passage for exhaust anode chamber R _2. Note that the rib 5d is crushed when the joined body and the anode container are brought into close contact with each other by pressing or the like during welding, and does not hinder welding.

FIG. 3 shows an example of the anode fitting 5 in which eight ribs 5 d are formed at equal intervals. However, in the present invention, the number of ribs is not limited, and the rib shape is not particularly limited. The anode fitting 5 may be made by cutting a metal material such as aluminum or an aluminum alloy. However, first, the metal material is first formed by cold forging into a rough shape of the metal fitting, and then is formed into a predetermined shape. It is preferably manufactured by processing to the shape of the metal fitting. The rib 5d may be formed by forging at the same time when the rough shape is formed by cold forging, or may be formed by cutting after cold forging.

When the metal material is formed into the shape of a metal fitting by cold forging and then processed into a predetermined metal fitting shape to produce the anode metal fitting 5, the metal material is formed by the first cold forging. At the same time as the general shape of the anode fitting is given, high strain is given to the metal structure. Then, when the metal structure subjected to such high strain is heated at the time of hot-pressure bonding with the insulating ring in the production of the joined body later, the crystal grains in the metal structure are refined, and this is an anode active material. Corrosion resistance and fatigue durability against sodium and sodium polysulfide generated during discharge are improved.

[0025] In this method of manufacturing the anode fitting, after the metal material is given the approximate shape of the fitting by cold forging,
This is processed into a predetermined metal fitting shape, and at least the upper surface of the lower flange portion 5c that is hot-press bonded to the insulating ring is processed into the predetermined shape by cutting.

The first step of forming by cold forging is performed by die forging using a forging die. At this time, in order to facilitate release after forging, a release material is formed of a metal material or a forging die. Is applied. Therefore, the surface of the molded body after forging is in a state where the release material is attached,
If the release material is not completely removed and the thermal pressure bonding with the insulating ring is performed in a state where the release material remains on the upper surface of the lower flange portion, a good bonding state cannot be obtained, and it cannot be put to practical use. Therefore, at least the upper surface of the lower flange portion 5c is machined by a cutting process to give a predetermined shape, and at the same time, the attached release material is completely removed.

The method of processing a portion other than the upper surface of the lower flange portion 5c to a desired predetermined metal fitting shape is not particularly limited, and is a cutting process like the upper surface of the lower flange portion 5c. It may be processed by another processing method. In addition, the portion may be formed to a desired predetermined shape in the first cold forging step.

In the assembling method of the present invention, the joined body to be welded to the anode container body has the same structure as that of the related art except that the anode fitting 5 having the rib 5d as shown in FIG. 3 is used. Having. That is, as shown in FIG. 4, in the joined body 1, the upper portion of the outer peripheral surface of the solid electrolyte tube 13 having a bottomed cylindrical shape is glass-bonded to the lower portion of the inner peripheral surface of the insulating ring 3.

The anode fitting 5 has a cylindrical portion 5 a as described above.
And an upper flange portion 5b extending outward from the upper end of the cylindrical portion 5a, a lower flange portion 5c extending inward from the lower end of the cylindrical portion 5a, and a rib 5d provided below the upper flange portion 5b. The upper surface of the lower flange portion 5c is hot-press bonded to the lower end surface of the insulating ring 3. Also,
The cathode metal fitting 7 has a cylindrical portion 7a and a flange portion 7b projecting outward from the outer periphery of the cylindrical portion 7a.
The lower surface of b is joined to the upper end surface of the insulating ring 3 by heat and pressure.

Next, of the components of the sodium-sulfur battery, portions not mentioned in the assembling method of the present invention will be described. These components are attached to the sodium-sulfur battery in the same manner as in a conventional assembly method. That is, as shown in FIG. 6, a cartridge 15 containing sodium is arranged inside a solid electrolyte tube 13 serving as a cathode chamber R _1, and a cathode lid 19 is provided above the cathode fitting 7.
The bonded to seal the cathode chamber R _1. Further, a cathode terminal 23 is provided on the upper surface of the cathode lid 19 and the outer peripheral portion of the anode container 9 respectively.
And the anode terminal 21 are joined.

A passage hole 17 is provided at the bottom of the cartridge 15.
Are penetrated to allow passage of sodium between the inside and outside of the cartridge 15. At the top of the cartridge 15, sodium azide is arranged similarly to the anode chamber R ₂ as a gas generating device, the battery is vaporized by thermal decomposition becomes the operating temperature nitrogen gas is generated, the cathode chamber R ₁ The pressure is increased to a predetermined pressure.

[0032]

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

Using an anode fitting 5 having eight ribs 5 d (rib apex angle 90 °) formed at equal intervals as shown in FIG. 3, an insulating ring 3, a solid electrolyte tube 13, and an anode as shown in FIG. The joined body 1 of the metal fitting 5 and the cathode metal fitting 7 was produced. Also,
Similarly, using a conventional anode fitting without ribs, a joined body 1 of the insulating ring 3, the solid electrolyte tube 13, the anode fitting 5, and the cathode fitting 7 as shown in FIG. 7 was produced. In addition, these joined bodies have a size suitable for a sodium-sulfur battery having a diameter of 90 mm. These joined bodies were fitted into a cylindrical anode container body, the contact interface between the anode fitting of the joined body and the anode container body was welded, and the eccentricity of the solid electrolyte tube after welding was measured.

The welding and the measurement of the amount of eccentricity were performed five times for each of the joined body using the anode fitting with the rib and the joined body using the anode fitting without the rib. Table 1 shows the measurement results. As shown in Table 1, the eccentricity of the solid electrolyte tube after welding of the joined body using the ribbed anode fitting according to the present invention is an average of 0.40 mm and does not affect the battery characteristics. It was 以下 or less of the eccentricity of the solid electrolyte tube after welding of the joined body using the anode metal fitting without.

[0035]

[Table 1]

[0036]

As described above, according to the assembling method of the present invention, as in the conventional assembling method, after the joined body of the insulating ring, the solid electrolyte tube, the anode fitting and the cathode fitting is welded to the anode container body, Since it does not include the step of inverting the battery, even when assembling a large-sized sodium-sulfur battery, a large burden is not imposed on the operator, and high productivity can be obtained. Further, in this assembling method, by using an anode fitting having ribs formed in the production of the joined body, centering of the solid electrolyte tube when welding the joined body to the anode container body, and air in the anode chamber are performed. Can be easily exhausted.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one step of the assembling method of the present invention.

FIG. 2 is a cross-sectional view showing the next step of the assembling method of the present invention.

FIGS. 3A and 3B are diagrams showing an anode fitting of the present invention, in which FIG. 3A is a side view showing a part in cross section, and FIG. 3B is a plan view seen from below.

FIG. 4 is a cross-sectional view showing a joined body of an insulating ring, a solid electrolyte tube, an anode fitting, and a cathode fitting made by the assembling method of the present invention.

FIG. 5 is a cross-sectional view showing an eccentric state of the solid electrolyte tube.

FIG. 6 is a sectional view showing an example of the structure of a sodium-sulfur battery.

FIG. 7 is a cross-sectional view showing a joined body of an insulating ring, a solid electrolyte tube, an anode fitting, and a cathode fitting.

FIG. 8 is a cross-sectional view showing one step of a conventional assembling method.

FIG. 9 is a sectional view showing the next step of the conventional assembling method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Joint body, 3 ... Insulation ring, 5 ... Anode fitting, 5a ... Cylindrical part, 5b ... Upper flange part, 5c ... Lower flange part,
5d: rib, 7: cathode metal fitting, 7a: cylindrical portion, 7b: flange portion, 9: anode container, 9a: anode container body, 9b: bottom cover, 10: constricted, 11: anode mold, 13: solid electrolyte tube, Reference numeral 15: cartridge, 17: passage hole, 19: cathode cover, 21: anode terminal, 23: cathode terminal.

Claims (3)

[Claims] 1. An upper part of an outer peripheral surface of a solid electrolyte tube having a bottomed cylindrical shape is glass-bonded to a lower part of an inner peripheral surface of an insulating ring, and furthermore, a cylindrical part and an upper flange part projected outward from an upper end of the cylindrical part. The upper surface of the lower flange portion of the anode fitting having a lower flange portion protruding inward from the lower end of the cylindrical portion and a rib provided below the upper flange portion on the lower end surface of the insulating ring, In addition, a joined body in which the lower surface of the flange portion of the cathode metal fitting having a cylindrical portion and a flange portion that protrudes outward from the outer periphery of the cylindrical portion to the upper end surface of the insulating ring is respectively hot-pressed is prepared. The anode mold is previously housed together with sodium azide in a cylindrical anode container body having a constriction, and a bottom lid is fixed by welding to one opening, and then the other opening of the anode container body is turned upward. The joint body is fitted into the opening in the closed state, and the contact interface between the anode container body and the anode fitting is welded and sealed. 2. A cylindrical portion, an upper flange portion extending outward from an upper end of the cylindrical portion, a lower flange portion extending inward from a lower end of the cylindrical portion, and a rib provided below the upper flange portion. And an anode fitting having: 3. The above-mentioned anode metal fitting is obtained by forming a metal material into a general shape of metal fitting by cold forging, and then processing it into a predetermined metal fitting shape. The anode fitting according to claim 2, wherein the processing for the upper surface of the anode is performed by cutting.