JP2002056887A - Method for manufacturing thermo-compression joining member for insulating ring constituting sodium-sulfur battery and positive electrode metal fitting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a thermo-compression joining member without generating local corrosion in positive electrode metal fitting, even if a sodium-sulfur battery is used as a battery over a long period. SOLUTION: This method is the manufacturing method for the thermo- compression joining member of a ceramic insulating ring 1 and aluminum or aluminum alloy positive electrode metal fitting 2 to be components of the sodium-sulfur battery. The shape of the positive electrode metal fitting 2 is constituted of a flange part 2a and a cylindrical part 2b. A joining prevention member 4 which does not join to a pressing jig 3 is interposed between surfaces that the pressing jig 3 for pressing the flange part 2a on a lower surface of the insulating ring 1 and the positive electrode metal fitting 2 contact. A demolding material is applied to a surface in contact with the positive electrode metal fitting 2 of the joining prevention member 4 in advance. After the thermo compression joining, the joining prevention member 4 is removed from the positive electrode metal fitting 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a heat-pressure joining member of an insulating ring and an anode fitting constituting a sodium-sulfur unit cell used as a secondary battery for power storage or the like, and used as a battery for many years. The present invention relates to a method for manufacturing a hot-pressed joining member between an insulating ring and an anode fitting for preventing corrosion of the anode fitting which occurs when the heat treatment is performed.

[0002]

2. Description of the Related Art A sodium-sulfur battery is used in a power storage system for realizing functions such as power leveling and peak cut, and the structure of the sodium-sulfur cell is shown in FIG. This is as schematically shown in the figure.

The battery structure at the time of manufacture is such that a bottomed cylindrical beta-alumina solid electrolyte tube 6 is glass-bonded to the inner peripheral surface of the α-alumina insulating ring 1 at the upper end outer peripheral surface thereof. The cathode compartment, which is divided by the cathode fitting 7 joined to the cathode fitting, the cathode lid 8 welded to the cathode fitting, the insulating ring 1 and the beta-alumina solid electrolyte tube 6, has a bottomed cylindrical metallic safety tube 9 and the same. A sodium storage container 10 containing sodium and a small amount of sodium azide is disposed inside the safety tube, while the anode chamber is welded to the anode fitting 2 joined to the lower surface of the insulating ring and the anode fitting. Anode container 5, furthermore, a bottom lid 11 welded to the anode container, an insulating ring 1, and a beta-alumina solid electrolyte tube 6, and a carbon mat impregnated with sulfur is provided. A structure inert gas-filled, such as nitrogen in.

[0004] After assembling the unit cell by each member, in the process of raising the temperature to the operating temperature of the battery, sodium in the sodium storage container is melted and generated by decomposition of sodium azide contained in the upper portion of the sodium storage container. Due to the pressure of the nitrogen gas, the molten sodium flows out of the small holes provided at the bottom of the sodium storage container into the cathode chamber to fill the cathode chamber.

The battery operates at a temperature of 290 ° C. to 350 ° C., and sodium ion-conducts as sodium ions in the beta-alumina solid electrolyte tube, reacts with molten sulfur in the anode chamber, generates sodium polysulfide and discharges reaction. Progresses.
During charging, the reverse reaction proceeds, returning molten sodium to the cathode compartment.

In the sodium-sulfur battery having the above-described configuration, an insulating ring 1 made of α-alumina, which is a component of the battery, and an anode fitting 2 made of Al or an Al alloy are hot-press bonded.
The anode container 5 is welded to the anode fitting 2 to assemble the battery.

FIG. 10 is a cross-sectional view of a main part of the thermocompression bonding member. The method of hot-pressing the insulating ring 1 and the anode fitting 2 is as follows. The insulating ring 1 is placed in the anode fitting 2 having the flange 2a, the cylindrical part 2b, and the flange 2c at the upper end edge of the cylindrical part.
Insulation ring 1 with a pressing jig in a furnace atmosphere around ℃
The flange portion 2a of the anode fitting is press-bonded to the lower surface of the anode.

At this time, the flange portion 2a of the anode fitting is A
Since it is an alloy, it is soft and is hot-pressed to the lower surface of the insulating ring 1 while being rolled. When the pressing jig 3 is separated from the anode fitting 2 after the heat and pressure bonding, the anode jig 2 made of an Al alloy is joined to the pressing jig 3 so that the pressing jig 3 cannot be separated or the anode jig 2 and the insulating ring 1 Therefore, there has been a problem that the joint part of the anode is peeled off. For this reason, a joint preventing member (stainless steel cap) 4 has conventionally been provided between the surfaces of the anode fitting and the pressing jig in contact with each other.
I've been using

Since the stainless steel cap 4 and the pressing jig 3 are not joined, the pressing jig 3 can be easily separated after hot-press bonding. However, the stainless steel cap 4 is the anode fitting 2
The anode container has been welded to the flange of the anode fitting with the stainless steel cap 4 still joined to the anode fitting 2, and the battery has been assembled.

The battery assembled in this manner was operated as an assembled battery for nearly 10 years, and the battery was disassembled and analyzed for each operating year. As a result, as shown in FIG. 11, it was found that local corrosion occurred in the anode fitting 2 near the end points A and B of the stainless steel cap 4.

[0011] Some local corrosion occurs from about the fifth year, and the corrosion depth progresses with the number of years of operation. Table 1 shows the relationship between the operating years and the corrosion status. Table 1 shows the battery operating temperature 33.
This is data at 5 ° C. and a plate thickness of 1.2 mm on the side of the anode fitting.

[0012]

[Table 1]

In particular, it is considered that local corrosion near point A may cause stress during the operation of the battery. Therefore, the battery has been used as a collective battery for 10 years without any problem. It is desired that such local corrosion of the anode metal does not occur.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a heat source which does not cause local corrosion in the anode fitting even when used as a battery for many years. An object of the present invention is to provide a method for manufacturing a pressure bonding member.

[0015]

According to the present invention, there is provided a method of manufacturing a thermo-compression bonding member between a ceramic insulating ring, which is a component member of a sodium-sulfur battery, and an anode metal fitting made of aluminum or an aluminum alloy. The fitting has a flange portion and a cylindrical portion, and a pressing jig that presses the flange portion to the lower surface of the insulating ring and a joining preventing member that is not joined to the pressing jig are interposed between surfaces where the anode fitting contacts. Also, a mold release material is applied to a surface of the joining prevention member which is in contact with the anode fitting in advance, and the joining member is removed from the anode fitting after the heat-pressure joining. A method for manufacturing a joining member is provided.

Further, in the present invention, it is preferable that the joining preventing member is made of stainless steel. Further, it is preferable that the cylindrical portion of the anode metal fitting is close to the outer peripheral surface of the insulating ring, and that the pressing jig has a side expansion restricting portion that restricts the lower outer surface of the cylindrical portion from expanding. Furthermore,
It is preferable that the cylindrical portion of the anode fitting has a flange at the upper end for welding to the anode container.

Further, according to the present invention, in a method for manufacturing a thermo-compression bonding member between a ceramic insulating ring, which is a component member of a sodium-sulfur battery, and an aluminum or aluminum alloy anode metal, the shape of the anode metal is Rolled steel for general structural use or a machine comprising a flange portion and a cylindrical portion, wherein the pressing jig for pressing the flange portion against the lower surface of the insulating ring and the pressing jig are prevented from joining with a surface in contact with the anode metal fitting. There is provided a method for manufacturing a heat-pressure bonded member between an insulating ring and an anode fitting, characterized by using a structural carbon steel bonding prevention member.

Further, in the present invention, a cutout portion is provided on a lower outer peripheral surface of a cylindrical portion of the anode fitting, and a cylindrical portion of the joining preventing member is mounted in the cutout portion, and The outer diameter is preferably smaller than the outer diameter of the cylindrical part of the anode fitting.

Further, according to the present invention, in a method for producing a thermo-compression bonding member of a ceramic insulating ring, which is a component member of a sodium-sulfur battery, and an aluminum or aluminum alloy anode metal, the shape of the anode metal is An Al / S having an anode or an Al alloy between the surface where the anode fitting is in contact with a pressing jig comprising a flange portion and a cylindrical portion and which presses the flange portion on the lower surface of the insulating ring;
There is provided a method of manufacturing a hot-pressed bonding member between an insulating ring and an anode fitting, which is manufactured by interposing a bonding prevention member of a US clad material.

Further, in the present invention, the joining preventing member has a ring portion which rises in the direction of the insulating ring at the inner peripheral edge of the flange portion, and the inner peripheral diameter of the ring portion is the inner peripheral diameter of the insulating ring. Preferably, it is larger than the diameter.

Further, according to the present invention, in a method of manufacturing a thermo-compression bonding member between a ceramic insulating ring, which is a component of a sodium-sulfur battery, and an aluminum or aluminum alloy anode metal, the shape of the anode metal is A pressing jig, which comprises a flange portion and a cylindrical portion, and presses the flange portion against the lower surface of the insulating ring, and M
There is provided a method for producing a thermocompression bonding member between an insulating ring and an anode fitting, wherein the method is performed by interposing a bonding prevention member made of a g alloy.

In the present invention, it is preferable that the joining preventing member is a Mg—Al alloy or a Mg—Al—Mn alloy.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described, but it goes without saying that the present invention is not limited to the following embodiments. The present invention will be described based on FIG. 1 which is an example of the embodiment.

FIG. 1 is a sectional view of a main part when the insulating ring 1, the anode fitting 2, and the pressing jig 3 are respectively arranged at predetermined positions and are joined by hot-pressing. FIG. 2 is an exploded perspective view of a main part in which each member is set in a predetermined order. The illustration of the brazing material used between the insulating ring 1 and the anode fitting 2 is omitted. The anode fitting 2 has a flange portion 2a, a cylindrical portion 2b, and a flange portion 2c, and the insulating ring 1 is placed in the anode fitting 2.

A graphite-based release agent is applied to the inner surface of the stainless steel joining preventing member 4 composed of the flange portion 4 a and the cylindrical portion 4 b, is covered with the anode fitting 2, and is pressed by the pressing jig 3. The flange portion 2a of the anode fitting 2 is pressed in a state where it is interposed.

Since the anode fitting 2 is made of an Al alloy, it is soft and is hot-pressed to the insulating ring 1 while being rolled.
Although not shown, a brazing material is used to increase the heat and pressure bonding strength. The pressing jig 3 is provided with a side expansion restricting portion 3a. The flange 2a of the anode fitting 2 is subjected to a stress that expands at the same time as the flange portion 2a is rolled. Expansion of the lower portion of the cylindrical portion 2b is prevented. Further, since the pressing jig 3 is not joined to the joining preventing member 4, it can be easily detached after hot-press joining.

After the heat and pressure bonding, as shown in FIG. 3, the joining preventing member 4 is joined to the anode fitting 2, but the joining preventing member 4 is removed from the anode fitting 2. It can be easily removed by the action of the graphite release agent. The anode container 5 is welded to the flange 2c of the anode fitting 2 of the insulating ring 1 and the hot-press joining member of the anode fitting 2 thus manufactured. As shown in FIG. 4, since the lower part of the cylindrical part 2b of the anode fitting 2 is not expanded, the anode container 5 can be easily welded to the flange part 2c with high dimensional accuracy.

Further, since the joining prevention member 4 is removed after the heat and pressure joining, there is no need to provide a notch on the outer surface of the lower portion of the cylindrical portion of the anode fitting 2, and the process is omitted, and productivity is improved and cost is reduced. It becomes possible. After welding the anode container, a sodium-sulfur battery is assembled by the same manufacturing method as before.

After operating the sodium-sulfur battery thus assembled at a temperature of 450 ° C. for 7 years, the battery was disassembled, and the anode fitting was observed and examined. As a result, local corrosion did not occur in the anode fitting, and it was in a good state. The reason for setting the battery temperature to 450 ° C. is for an accelerated corrosion test of the anode fitting.

Next, the second invention (claim 5) of the present invention will be described. The method of manufacturing the thermal pressure bonding member between the insulating ring 1 and the anode fitting 2 is the same as the conventional method shown in FIG.

However, the joining prevention member 4 used in the present invention is a rolled steel for general structure (SS material) or a carbon steel for machine structure (SC material), and has excellent corrosion resistance as the conventional hot-pressure joining member 4. This is different from the method using the stainless steel cap 4. The joining prevention member 4 is still in a state of being joined to the anode fitting 2 even after the hot-pressure joining. Since the joining prevention member 4 is made of rolled steel for general structure (SS material) or carbon steel for machine structure (SC material), the pressing jig 3 can be easily separated after hot-press joining.

After the heat and pressure bonding, the anode container 5 is welded to the flange 2 c of the anode fitting 2. As shown in FIG. 5, the outer diameter of the cylindrical portion 4b of the joining prevention member 4 is smaller than the outer diameter of the cylindrical portion 2b of the anode fitting 2, so that the anode container 5 can be formed accurately and easily with the flange 2c of the anode fitting. Can be welded.

After welding the anode container, a sodium-sulfur battery is assembled by the same manufacturing method as before. Ten sodium-sulfur batteries assembled in this manner were heated at 450 ° C. for 7 hours.
After operating for a year, the battery was disassembled, and the anode fitting was observed and investigated.

As a result, all the joining prevention members have disappeared, and the vicinity of the point A of the anode fitting of the battery using SS41 as the joining prevention member (the front edge of the joining prevention member flange portion).
Up to 2μ near point B and near the edge of the cylindrical part of the joining prevention member
Several batteries with slight local corrosion of about m were observed, but other batteries did not show local corrosion and were in a good condition.

When the joining prevention member is an SS material or an SC material, it is corroded by sodium polysulfide vapor or melt in a short period of time when operating as a battery, and is separated from the anode fitting in a short period of time and disappears. Is estimated.

Next, the third invention (claim 7) of the present invention will be described. The method of arranging the insulating ring 1, the anode fitting 2, and the pressing jig 3 at predetermined positions and joining them by heat and pressure is the same as the conventional method shown in FIG. However, the difference is that the joining prevention member 4 used is an Al / SUS clad material in which the side in contact with the anode fitting 2 has Al or an Al alloy.

FIG. 6 shows a bonding preventing material for a clad material used in the present invention, (a) is a cross-sectional view thereof, and (b).
Shows a perspective view thereof. The part in contact with the pressing jig 3 is SUS
Therefore, the pressing jig 3 easily comes off after the hot-press bonding. After the thermocompression bonding, the bonding prevention member 4 of the clad material is in a state of being bonded to the anode fitting 2.

In this case as well, as shown in FIG. 5, the outer diameter of the cylindrical portion 4b of the joining prevention member 4 is smaller than the outer diameter of the cylindrical portion 2b of the anode fitting 2, so that the anode container 5 can be formed with high accuracy. It can be easily welded to the flange 2c of the anode fitting. After welding the anode container, a sodium-sulfur battery is assembled by the same manufacturing method as before.

After operating the 10 sodium-sulfur batteries thus assembled at a temperature of 450 ° C. for 7 years, the batteries were disassembled, and the anode fitting was observed and examined. As a result, local corrosion occurred in the aluminum portion at the tip of the clad material, but local corrosion was not generated to such an extent as to cause a problem in the anode fittings of all the batteries, and the condition was favorable.

As shown in FIG. 7, the shape of the joining prevention member 4 of the clad material is a shape in which a ring portion 4c that rises above the tip of the flange portion 4a is formed. As shown in FIG. The tip of the ring portion 4c of the joining preventing material is not in contact with the anode fitting 2.

In this case, similarly, as shown in FIG. 5, after welding the anode container, a sodium-sulfur battery is assembled by the same manufacturing method as that of the related art. After operating 10 sodium-sulfur batteries thus assembled at a temperature of 450 ° C. for 7 years, the batteries were disassembled, and the anode fitting was observed and investigated. As a result, local corrosion occurred in the aluminum portion of the clad material at the tip of the ring portion 4c of the joining prevention member 4, but local corrosion did not occur in the anode fittings of all the batteries. Met.

Next, a fourth invention (claim 9) of the present invention will be described. A method of arranging the insulating ring 1, the anode metal fitting 2, and the pressing jig 3 at predetermined positions and performing heat-pressure bonding is as follows.
It is the same as the conventional method. However, the difference is that the joining prevention member 4 is made of an Mg alloy. Incidentally, the Mg alloy has a greater ionization tendency than Al.

Similarly, in this case, the pressing jig can be easily separated after the heat and pressure bonding, and the anode container 5 is welded to the heat and pressure bonded anode fitting 2 to assemble the battery. After operating 10 sodium-sulfur batteries thus assembled at a temperature of 450 ° C. for 7 years, the batteries were disassembled, and the anode fitting was observed and investigated.

As a result, local corrosion hardly occurred in the anode fittings of all the batteries, and the battery was in a good condition.
In particular, Mg-Al or Mg-Al-Mn made of Mg alloy
It was even better when the alloy was used. The first to fourth inventions have been described above based on the examples. Table 2 shows the results of the measurement of the corrosion of the anode fitting at the end A of the joining prevention member (see FIG. 11).

[0045]

[Table 2]

[0046]

As described above, according to the present invention, in a method of manufacturing a thermo-compression bonding member between a ceramic insulating ring, which is a component of a sodium-sulfur battery, and an anode fitting, according to the present invention, an anode fitting of a joining prevention member is provided. A graphite-based mold release agent is applied in advance to the surface in contact with the substrate, and the joining prevention member is removed from the anode fitting after hot-press bonding, or the SS or SC material is used as the joining prevention member, or the joining is performed. By using an Al / SUS clad material whose surface in contact with the anode fitting is Al or an Al alloy for the prevention member, or by using a Mg alloy for the bonding prevention member, assembling as a battery after thermocompression bonding In addition, a special effect that local corrosion of the anode fitting can be prevented from being generated after many years of operation can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part when an insulating ring, an anode fitting, and a pressing jig of the present invention are arranged at predetermined positions and are joined by hot pressing.

FIG. 2 is an exploded perspective view of a main part in which respective members are set in a predetermined order when performing hot-pressure joining.

FIG. 3 is a cross-sectional view of a main part of the insulating ring, the anode fitting, and the joining preventing member after the heat and pressure joining of the present invention.

FIG. 4 is a sectional view showing a main part of welding the anode container to the thermocompression bonding member of the present invention.

FIG. 5 is a cross-sectional view of a main part of another embodiment of the present invention, in which an anode container is welded to a thermocompression bonding member.

FIG. 6 shows a clad material joining prevention member of the present invention.
(A) is a sectional view thereof, and (b) is a perspective view thereof.

FIG. 7 is a cross-sectional view showing another embodiment of the clad material joining preventing member used in the present invention.

FIG. 8 is a cross-sectional view of a main part of a thermocompression bonding member using the cladding material bonding prevention member of the present invention.

FIG. 9 is a schematic sectional view showing a conventional sodium-sulfur battery.

FIG. 10 shows a conventional alumina insulating ring and Al or A
FIG. 3 is a cross-sectional view of a main part when the 1-alloy anode metal fitting and the stainless steel cap are hot-press bonded by a pressing jig.

FIG. 11 is a sectional view of a main part showing a local corrosion site of an anode fitting when a conventional sodium-sulfur battery has been operated for many years.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulation ring, 2 ... Anode fitting, 2a ... Flange part, 2
b ... Cylindrical part, 2c ... Flange part, 2d ... Notch part, 2e ... Flange tip after hot press bonding, 3 ... Pressing jig, 3a ... Side expansion restricting part, 4 ... Junction prevention member, 4a ... Flange Part 4,
b: cylindrical portion, 4c: upper rising ring portion at the end of the flange portion, 5: anode container, 6: beta alumina solid electrolyte tube, 7: cathode metal fitting, 8: cathode cover, 9: safety tube, 10: sodium storage container , 11 ... Bottom lid.

Claims (10)

[Claims] 1. A method for producing a thermo-compression bonding member between a ceramic insulating ring, which is a component of a sodium-sulfur battery, and an aluminum or aluminum alloy anode fitting, wherein the shape of the anode fitting is changed from a flange portion and a cylindrical portion. A pressing jig that presses the flange portion against the lower surface of the insulating ring, and a joining preventing member that is not joined to the pressing jig is interposed between a surface where the anode fitting is in contact with the pressing jig. A method for manufacturing a thermo-compression joining member between an insulating ring and an anode fitting, wherein a release material is applied to a surface in contact with the fitting, and the joining preventing material is removed from the anode fitting after the thermo-compression bonding. 2. The method according to claim 1, wherein the joining preventing member is made of stainless steel. 3. A side expansion restricting portion for restricting a cylindrical portion of the anode metal fitting to an outer peripheral surface of the insulating ring and preventing the pressing jig from expanding the lower outer surface of the cylindrical portion of the anode metal fitting. The method according to claim 1, wherein the insulating ring and the anode fitting are manufactured by: 4. The anode fitting according to claim 3, wherein the cylindrical portion of the anode fitting has a flange at the upper end for welding to the anode container.
3. A method for producing a thermocompression bonding member between an insulating ring and an anode fitting according to claim 1. 5. A method of manufacturing a thermo-compression bonding member between a ceramic insulating ring, which is a component of a sodium-sulfur battery, and an aluminum or aluminum alloy anode fitting, wherein the shape of the anode fitting is changed from a flange portion and a cylindrical portion. And joining of a rolled material for general structure or carbon steel for machine structure to prevent joining between the pressing jig pressing the flange portion to the lower surface of the insulating ring and the pressing jig between surfaces contacting the anode fitting. A method for manufacturing a thermo-compression bonding member between an insulating ring and an anode fitting, wherein the method includes manufacturing with a prevention member interposed. 6. A notch portion is provided in a lower outer peripheral surface of a cylindrical portion of the anode fitting, a cylindrical portion of the joining preventing member is mounted in the notch portion, and an outer diameter of the cylindrical portion is equal to that of the anode. The method according to claim 5, wherein the outer diameter is smaller than the outer diameter of the cylindrical portion of the metal fitting. 7. A method for producing a thermo-pressure joining member of a ceramic insulating ring, which is a component member of a sodium-sulfur battery, and an aluminum or aluminum alloy anode fitting, wherein the shape of the anode fitting is changed from a flange portion and a cylindrical portion. And a pressing jig for pressing the flange portion against the lower surface of the insulating ring and a surface in contact with the anode fitting between the pressing jig and the surface in contact with the anode fitting.
Alternatively, a method for producing a hot-pressed joining member between an insulating ring and an anode fitting, wherein the joining member is produced by interposing a joining prevention member of an Al / SUS clad material made of an Al alloy. 8. The joining prevention member has a ring portion rising on the inner peripheral edge of the flange portion in the direction of the insulating ring, and the inner peripheral diameter of the ring portion is larger than the inner peripheral diameter of the insulating ring. A method for manufacturing a heat-pressure bonded member between an insulating ring and an anode fitting according to claim 7. 9. A method for producing a thermo-compression bonding member between a ceramic insulating ring, which is a component of a sodium-sulfur battery, and an aluminum or aluminum alloy anode fitting, wherein the shape of the anode fitting is changed from a flange portion and a cylindrical portion. And an insulating ring and an anode fitting manufactured by interposing a joining preventing member made of Mg alloy between a pressing jig that presses the flange portion against the lower surface of the insulating ring and a surface where the anode fitting contacts. And a method for producing a thermo-compression bonding member. 10. The method according to claim 9, wherein the joining preventing member is an Mg—Al alloy or an Mg—Al—Mn alloy.
3. A method for producing a thermocompression bonding member between an insulating ring and an anode fitting according to claim 1.