JPH079816B2 - Thermo-compression bonding method of insulating ring and electrode fitting in sodium-sulfur battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermocompression bonding method for an insulating ring and electrode fittings of an anode and a cathode in a sodium-sulfur battery.

[Prior Art] As shown in FIG. 7 as a conventional sodium-sulfur battery, a bottomed cylindrical anode container 22 for accommodating molten sulfur S as an anode active material and an upper inner side of the anode container 22 are provided. , Through the anode metal fitting 23 composed of the cylindrical portion 23a and the flange portion 23b α-
Insulation ring 24 made of alumina is fitted and fixed
An upper outer peripheral surface of a bottomed cylindrical solid electrolyte tube 25 made of polycrystalline β ″ -alumina having a function of selectively permeating sodium ions Na ⁺ to the inner peripheral surface of 24 is fixedly bonded to the inner peripheral surface of 24. Further, a cylindrical portion is provided at the upper end of the insulating ring 24.
Fit and fix the cathode metal fitting 26 consisting of 26a and the flange portion 26b,
In some cases, a flat plate-shaped cathode lid 27 was brought into contact with and welded to the upper end of the cathode metal fitting 26. The solid electrolyte tube 25 divides the inside of the battery into an anode chamber R1 for storing molten sulfur S and a cathode chamber R2 for storing sodium Na.

During discharge, sodium becomes sodium ion Na ⁺ from the cathode chamber R2 and permeates the solid electrolyte tube 25 to pass through the anode chamber R2.
It reacts with sulfur S in 1 as follows to produce sodium polysulfide.

2Na + XS → Na ₂ Sx Also, during charging, a reaction reverse to that during discharging occurs, and sodium Na and sulfur S are produced.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional battery, when the anode metal fitting 23 and the cathode metal fitting 26 are thermocompression bonded to the insulating ring 24, a stainless steel bonding pressure jig is made of aluminum or aluminum. Since it was in direct contact with the anode metal fittings 23 and the cathode metal fittings 26 made of alloy, the joining pressure jigs adhered to the anode metal fittings 23 and the cathode metal fittings 26 due to the difference in the material of the pressure fittings and the metal fittings 23, 26. Therefore, the separation of the pressure jig is not only troublesome, but also when the pressure jig is separated, the joint interface between the insulating ring 24 and the anode metal fitting 23 and the cathode metal fitting 26 receives tension, There is a problem that the joint strength and the assembly dimensional accuracy are reduced.

In order to solve this problem, for example, if the material of the cathode metal fitting 23 and the cathode metal fitting 26 is stainless steel, it is possible to prevent the adhesion with the pressing jig, but not only the electric resistance increases and the battery efficiency decreases, but also the heat conduction And the temperature distribution of the battery becomes non-uniform.

Further, at the time of the hot pressure bonding, the cylindrical portions 23a, 26a of the anode metal member 23 and the cathode metal member 26 expand in the radial direction under the influence of the pressing force, and it is necessary to polish them, which causes a problem that the work efficiency is reduced. It was

Further, when the intermediate joining ring is pressed, the cathode side tends to widen in the outer circumferential direction and the anode side tends to widen in the inner circumferential direction.
Insulation of the cathode and anode was uncertain.

A first object of the present invention is to prevent the adhesion of the electrode fitting and the joining pressure jig to improve the joining strength between the insulating ring and the electrode fitting, and to improve the assembling accuracy of the insulating ring and the electrode fitting. Another object of the present invention is to provide a method for thermocompression bonding of an insulating ring and an electrode fitting in a sodium-sulfur battery, which can improve the durability and reliability of the battery.

A second object of the present invention is, in addition to the above first object, that the expansion due to the crushing of the intermediate joining ring can be limited to improve the insulating properties of the anode fitting and the cathode fitting, and the insulating ring, the anode fitting, and To provide a thermocompression bonding method for an insulating ring and an electrode metal fitting in a sodium-sulfur battery that can prevent the expansion of the cylindrical portion of both metal fittings near the joint surface with the cathode metal fitting and improve the assembly accuracy. is there.

In addition to the above-mentioned second object, the third object of the present invention can more reliably prevent the expansion of the insulating ring and the cylindrical parts of the anode fitting and the cathode fitting to improve the assembling accuracy. It is an object of the present invention to provide a thermocompression bonding method for an insulating ring and an electrode fitting in a sodium-sulfur battery.

Further, a fourth object of the present invention is, in addition to the above-mentioned second object, of the insulating ring and the electrode fitting in the sodium-sulfur battery which can further improve the assembling accuracy of the insulating ring and the anode fitting and the cathode fitting. It is to provide a hot press bonding method.

[Means for Solving the Problems] In order to achieve the first object of the invention of claim 1, the flange of the electrode fitting made of aluminum or aluminum alloy having a cylindrical portion and a flange portion with respect to the ceramic insulating ring. A method of interposing a stainless steel plate between the electrode fitting and the joining pressure jig is adopted when the parts are joined by thermocompression.

In order to achieve a second object, the invention according to claim 2 interposes a first joining ring between the insulating ring and the flange portion of the anode metal fitting as the electrode metal fitting in claim 1, Further, the cylindrical portion formed on the inner peripheral edge of the first stainless plate covers the inner peripheral edge of the flange portion and the inner peripheral edge of the first joint ring to perform thermocompression bonding, thereby forming the insulating ring and the electrode fitting. The second intermediate joining ring is interposed between the flange part of
Furthermore, a method is employed in which the cylindrical portion formed on the outer peripheral edge of the second stainless plate covers the outer peripheral edge of the flange portion and the outer peripheral edge of the second joint ring to perform thermocompression bonding.

In order to achieve the third object, the invention according to claim 3 forms the cylindrical portion on the outer peripheral edge of the first stainless steel plate and the cylindrical portion on the inner peripheral edge of the second stainless steel plate. It is formed, and the height of each of the cylindrical portions from the bottom surface is set to be longer than the distance from the bottom surface to the end surface of the insulating ring.

Further, in order to achieve the fourth object, the invention according to claim 4 provides the first stainless steel ring in the vicinity of the first stainless steel plate to the outer peripheral surface of the cylindrical portion of the anode fitting in the second invention. A method is adopted in which the second stainless steel ring is fitted to the inner peripheral surface of the cylindrical portion of the cathode fitting in close proximity to the second stainless steel plate.

[Operation] Since the invention according to claim 1 interposes the stainless steel plate for facilitating the separation between the anode metal fitting and the cathode metal fitting made of aluminum or aluminum alloy and the pressure jig for the thermocompression bonding, The pressing jig can be quickly separated after the thermo-compression bonding without applying excessive tensile force to the anode fitting and the cathode fitting to improve the work efficiency.
Assembling accuracy of the insulating ring and both electrode fittings is improved.

According to the second aspect of the present invention, the cylindrical portion formed at the inner peripheral edge or the outer peripheral edge of the stainless plate can limit the expansion of the intermediate joining ring due to crushing, and improve the insulating properties of the cathode fitting and the anode fitting. Further, it is possible to prevent the metal fittings from bulging in the vicinity of the joint surface between the insulating ring and the cathode fitting and the anode fitting, thereby improving the assembling accuracy.

According to a third aspect of the present invention, the height of the cylindrical portion formed on the outer side of the first stainless plate from the bottom surface is set longer than the distance from the bottom surface to the end surface of the insulating ring. It is possible to suppress the expansion of the cylindrical portion of the anode fitting by the expansion of the ring in the radial direction, and to improve the assembling accuracy of the insulating ring and the anode fitting.

Further, by setting the height from the bottom surface of the cylindrical portion formed inside the second stainless plate to be longer than the distance from the bottom surface to the end surface of the insulating ring, the inner side in the radial direction of the second intermediate joining ring. It is possible to suppress the expansion of the cylindrical portion of the cathode fitting due to the expansion of the cathode fitting, thereby improving the accuracy of assembling the insulating ring and the cathode fitting.

According to the invention described in claim 4, since the bulges of the both cylindrical portions are surely prevented, the assembling accuracy is further improved.

[Embodiment] An embodiment in which a sodium-sulfur battery is embodied will be described below with reference to FIGS. 1 to 3.

As shown in Figs. 1 and 3, insulating ring 1 made of α-alumina
The flange portion 3b of the aluminum or aluminum alloy anode metal fitting 3 including the cylindrical portion 3a and the flange portion 3b is attached to the lower end surface 1a of the aluminum alloy via the first intermediate joining ring 2 made of the aluminum alloy, which will be described later in detail. It is fixed by the thermocompression bonding method. Further, the upper inner peripheral surface of the anode container 4 having a vertically elongated cylindrical shape with a bottom is fitted to the cylindrical portion 3a of the anode metal fitting 3, and the upper end edges of both are sealed by the welded portion 5A.

On the inner peripheral surface of the insulating ring 1, the upper end outer peripheral surface of the solid electrolyte tube 6 made of β ″ -alumina and having a bottomed tubular shape is adhered and fixed by glass fusion or the like.

A cylindrical portion 8a and a flange portion are formed on the upper end surface 1b of the insulating ring 1 via a second intermediate joining ring 7 made of an aluminum alloy.
The flange portion 8b of the cathode metal fitting 8 made of aluminum or aluminum alloy consisting of 8b is fixed by a thermocompression bonding method described in detail later.

A cap-shaped metal fitting 9 composed of a cylindrical portion 9a and an upper plate portion 9b is fitted on the inner peripheral surface of the cylindrical portion 8a. Then, the entire upper edges of both the cylindrical portions 8a and 9a are sealed by the welded portion 5B.

A chamfered portion 1c is formed at an inner corner of the upper surface of the insulating ring 1 to prevent the intermediate joining ring 7 from being cut off. The radius R of the chamfered portion 1c is set to 0.4 ± 0.1 mm.

An anode conductive material M such as carbon mat impregnated with molten sulfur S as an anode active material is housed in an anode chamber R1 formed between the anode container 4 and the solid electrolyte tube 6. Further, metallic sodium Na as a cathode active material is stored in the cathode chamber R2.

When the sodium-sulfur battery is completely charged, most of the sodium is stored in the cathode chamber R2 as shown by the solid line in FIG. 3, and the molten sulfur S is present in the cathode conductive material M. When the discharge is started in this state, sodium Na in the cathode chamber R2 becomes sodium ions, permeates the solid electrolyte tube 6, and reacts with sulfur S in the conductive material M for the anode to generate sodium polysulfide.

Next, the thermocompression bonding method of the present invention will be described with reference to FIGS. 1 and 2.

Before performing thermocompression bonding, the insulating ring 1, the first and second intermediate bonding rings 2 and 7, the anode fitting 3, the cathode fitting 8 and the first and second
The stainless steel plates 12 and 13 are stacked in order as shown in FIG. Although not shown, the lower end surface of the insulating ring 1
1a has a first intermediate joining ring 2, an anode fitting 3, and a cylindrical portion 12a.
1st stainless steel plate 1 consisting of and flange 12b
2 and the first pressing jig 10 are arranged in this order. Further, on the upper end surface 1b of the insulating ring 1, the second intermediate joining ring 7, the cathode fitting 8, the second stainless plate 13 including the cylindrical portion 13a and the flange portion 13b, and the second pressing jig 11 are arranged in this order. To do.

Then, pressurizing jigs 10, 11 in an inert gas atmosphere at about 600 ° C.
Insulating ring 1 while pressurizing each member by
The anode metal fitting 3 and the anode metal fitting 3 are thermocompression bonded by the action of the bonding ring 2, and the insulating ring 1 and the cathode metal fitting 8 are thermocompression bonded by the action of the bonding ring 7. Then, the state shown in FIG. 1 is obtained in the final step of the thermocompression bonding.

Since the stainless steel plates 12 and 13 are used in the above embodiment, the adhesion of the anode metal fitting 3 and the pressure jig 10 is prevented, and the adhesion of the cathode metal fitting 8 and the pressure jig 11 is prevented. Work becomes easy and pressure jigs 10, 11
It is possible to prevent an unreasonable force from acting on the anode metal fitting 3 and the cathode metal fitting 8 at the time of separation, to suppress a decrease in bonding strength, and further to maintain the assembling accuracy.

Further, in the above-mentioned embodiment, the cylindrical portions 12a and 13a of the stainless steel plates 12 and 13 can limit the expansion of the intermediate joining rings 2 and 7 due to the crushing and improve the insulating properties of the anode fitting 3 and the cathode fitting 8. .

Next, another embodiment of the present invention will be described with reference to FIGS.

In another example shown in FIG. 4, a step portion 3c is formed on the outer peripheral surface of the cylindrical portion 3a of the anode fitting 3, and a cylindrical portion 12c integrally formed on the outer peripheral edge of the stainless plate 12 is fitted to the step portion 3c. The bulge of the cylindrical portion 3a of the anode fitting 3 is prevented. Similarly, a step portion 8c is also formed on the cathode metal fitting 8 side, and a cylindrical portion 13c engaged with the step portion 8c is integrally formed on the inner peripheral edge of the stainless plate 13.

Further, the height H1 from the bottom surface 12d, 13d of the cylindrical portion 12c, 13c
Is set to be equal to or longer than the distance H2 from the bottom surface 12d, 13d to the lower end surface 1a, the upper end surface 1b of the insulating ring 1 to more reliably prevent the bulging of the cylindrical portions 3a, 8a,
The assembly accuracy is improved. That is, in FIG. 4, when the height H1 of the cylindrical portion 12c is lower than the height H2, when the first intermediate joining ring 2 is crushed during thermocompression joining, the ring 2 swells radially outward. Since the proof stress to limit it is weak, the deformation of the cylindrical portion 3a becomes large. Further, in the above-described embodiment, the height H1 of the cylindrical portion 13c is equal to or greater than the height H2, so that the force that opposes the inward expansion in the radial direction due to the collapse of the second intermediate joining ring 7. Is increased and deformation of the cylindrical portion 8a is suppressed.

Another example shown in FIG. 5 is a cylindrical portion 12c, 1 of another example shown in FIG.
The first and second stainless steel rings 14 and 15 having the same function as 3c are independently formed and fitted into the stepped portions 3c and 8c for thermocompression bonding.

Another example shown in FIG. 6 is the same as the other example shown in FIG.
The stainless rings 14 and 15 described in the figure are used, and the ring 15 is fitted on the inner peripheral surface of the cylindrical portion 8a of the cathode fitting 8. Therefore, in this embodiment, the swelling prevention effect at the time of hot-pressing the anode metal fitting 3 is further improved, and since the step portion 8c does not have to be formed on the cathode metal fitting 8, the manufacturing is facilitated.

The stainless steel plates 12 and 13 remain attached to the anode fitting 3 and the cathode fitting 8 after the thermocompression bonding.

[Advantages of the Invention] As described in detail above, the invention according to claim 1 can improve the bonding strength between the insulating ring and the anode fitting and the cathode fitting, and at the same time, assembles the insulating ring, the anode fitting and the cathode fitting. The accuracy can be improved, and the durability and reliability of the battery can be improved.

According to the second aspect of the present invention, the cylindrical portion formed on the inner peripheral edge or the outer peripheral edge of the stainless steel plate can limit the expansion of the intermediate joining ring due to crushing and improve the insulating properties of the cathode fitting and the anode fitting. Further, there is an effect that both fittings in the vicinity of the joint surface between the insulating ring and the cathode fitting and the anode fitting can be prevented from bulging to improve the assembling accuracy.

The invention according to claim 3 has an effect that the bulging of the cylindrical portion of both metal fittings near the joint surface between the insulating ring and the cathode metal fitting and the anode metal fitting is more surely prevented to improve the assembling accuracy. .

According to the invention described in claim 4, since the bulges of the both cylindrical portions are surely prevented, there is an effect that the assembling accuracy can be further improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a sodium-sulfur battery embodying the present invention in a state in which thermocompression bonding is completed only for essential parts,
FIG. 2 is an exploded perspective view of a main part, FIG. 3 is a vertical cross-sectional view of a central portion showing the entire sodium-sulfur battery, and FIGS. 4 to 6 are cross-sectional views of only the main part showing another example of the present invention. FIG. 7 is a vertical cross-sectional view of a central portion showing a conventional example. 1 ... Insulation ring, 1a ... Lower end surface, 1b ... Upper end surface, 2,7
...... First and second intermediate joining rings, 3 ...... Anode fittings, 3a …… Cylinder part, 3b …… Flange part, 4 …… Anode container, 6 …… Solid electrolyte tube, 8 …… Anode fittings, 8a …… Cylinder part, 8b …… Flange part, 10,11 …… Pressure jig, 12,13 ……
Stainless plate, 12a, 12c, 13a, 13c …… Cylindrical part, 12
b, 13b …… flange part, 12d, 13d …… bottom surface, 14,15 …… stainless steel ring, M …… anode conductive material, R1 …… anode chamber,
R2 ... Cathode chamber.

Claims (4)

[Claims] 1. An electrode fitting (3,8) made of aluminum or an aluminum alloy having a cylindrical portion (3a, 8a) and a flange portion (3a, 8b) with respect to a ceramic insulating ring (1).
At the time of thermocompression-bonding the flange portions (3a, 8b), a stainless steel plate (12, 13) is interposed between the electrode fittings (3, 8) and the joining pressure jig (10, 11). A method for thermocompression-bonding an insulating ring and an electrode fitting in a sodium-sulfur battery. 2. A first intermediate joining ring (2) is interposed between the insulating ring (1) and the flange portion (3b) of the anode metal fitting (3) as the electrode metal fitting, and the first intermediate joining ring (2) is further provided. Cylindrical part (12
With a), the inner peripheral edge of the flange portion (3b) and the inner peripheral edge of the first intermediate joint ring (2) are covered to perform thermocompression bonding, and the insulating ring (1) and the cathode metal fitting ( The second intermediate joint ring (7) is interposed between the flange portion (8b) of 8) and the cylindrical portion (13a) formed on the outer peripheral edge of the second stainless steel plate (13). The insulating ring and the electrode fitting in the sodium-sulfur battery according to claim 1, wherein the flange part (8b) and the second intermediate joining ring (7) are covered with the outer periphery of the flange and the outer periphery of the second intermediate joining ring to perform thermocompression bonding. Hot pressure bonding method. 3. A cylindrical portion (12c) is formed on the outer peripheral edge of the first stainless plate (12), and a cylindrical portion (13c) is formed on the inner peripheral edge of the second stainless plate (13). The height (H1) from the bottom surface (12d, 13d) of the cylindrical portion (12c, 13c) is measured from the bottom surface (12d, 13d) to the end surface (1a, 1b) of the insulating ring (1). The method for thermocompression bonding between an insulating ring and an electrode fitting in a sodium-sulfur battery according to claim 2, wherein the method is set longer than (H2). 4. A first stainless steel ring (14) is fitted close to the first stainless steel plate (12) on the outer peripheral surface of the cylindrical portion (3a) of the anode fitting (3), A second stainless steel ring (15) is fitted to the inner peripheral surface of the cylindrical portion (8a) of the cathode fitting (8) in proximity to the second stainless steel plate (13). 2. A method for thermocompression bonding an insulating ring and an electrode fitting in a sodium-sulfur battery according to 2.