JP2001035527A - Insulating ring and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulating ring, in which each of the connection part of the insulating ring with a solid electrolytic tube and the connection part of the insulating ring with a metallic member can form a connection part which is highly reliable with respect to thermal or mechanical stress by providing a projection on at least a part of the upper end surface and/or lower end surface of the insulating ring. SOLUTION: Since projections on the upper end surface and/or lower end surface of an insulating ring is provided as the contact surface with a setter in the baking thereof, the projection does not necessarily have to be on the outer periphery side of the upper end surface or the inner periphery side of the lower end surface, but may be located on the inner periphery side of the upper end surface or the outer periphery side of the lower end surface. When the projections are provided on both the upper and lower end surfaces, baking can be performed in the state where the projection on either of the upper and lower end surfaces is set on the lower side and touched to the setter. Since the part making contact with a baking jig is limited to only the projection in this insulating ring, the surface roughness of the connecting part with metal will not deteriorate, the contacting area is also significantly minimized, and the dimensional precision even in the sintered body prior to polishing is improved significantly and the need for polishing work is dispensed with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating ring and a method for manufacturing the same. More specifically, for example, a sodium-sulfur battery, a sodium-molten salt battery, AMTEC, or SO
The present invention relates to an insulating ring used for an x-sensor and the like, which relates to a shape of an insulating ring which is effective for improving reliability of a joint with a solid electrolyte tube made of beta-alumina and to reduce the cost of those devices, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A sodium-sulfur battery has a cathode chamber filled with sodium as a cathode active material and a sulfur chamber as an anode active material in a completely sealed battery case so as not to be affected by air, moisture and the like. And a high-temperature secondary battery in which an anode chamber filled with is filled and separated by a solid electrolyte tube made of beta-alumina. FIG. 1 shows a typical structure of a sodium-sulfur battery.

At the open end of the solid electrolyte tube (1), an insulating ring (2) made of an insulating ceramic such as α-alumina is provided.
Are bonded using a bonding glass (3). After the cathode side metal member (4) and the anode side metal member (5) are hot-press bonded to the upper and lower end surfaces of the insulating ring (2), an active material of sodium (6) and sulfur (7) is filled. The battery is obtained by sealing the lid (8) and the battery case (9) on the anode side by welding or the like. Incidentally, (10) in FIG. 1 is a cathode terminal.

[0004] Examples of preferable shapes of the insulating ring used for the sodium-sulfur battery are disclosed in Japanese Patent Application Laid-Open Nos. Hei 3-182055 and Hei 6-196204.

[0005] Japanese Patent Application Laid-Open No. Hei 3-182055 discloses an insulating ring in which a projection is provided on at least one of an outer peripheral upper end surface and an inner peripheral lower end surface of the insulating ring. These projections can prevent excessive deformation of the metal members generated when the cathode-side metal member and the anode-side metal member are joined by heat and pressure, reduce short circuit failure during battery assembly, and reduce the joining strength of the metal member joint. It is said to be effective in reducing variation.

However, when glass bonding the insulating ring to the open end of the solid electrolyte, it is necessary to arrange a jig or the like for positioning both to perform glass bonding. This is because it is difficult to join them at a fixed position unless they are positioned using a jig or the like. At this time, there is a problem that the bonding glass adheres to the jig and the jig and the insulating ring or the solid electrolyte tube are fixed.

[0007] Also, sodium-sulfur batteries are exposed to a temperature ramp cycle between room temperature and operating temperature (300-350 ° C). At this time, the stress due to the difference in the thermal expansion coefficient of each member and the stress generated when the active material, which was liquid during operation, changes to a solid, act on the glass joint between the insulating ring and the solid electrolyte tube. With respect to the stress in the axial direction of the insulating ring (longitudinal direction of the solid electrolyte tube), stress concentrates on the glass joint having low strength, so that there is a problem that breakage easily occurs in this portion.

In order to solve such a problem, an insulating ring having a specific shape is disclosed in Japanese Patent Application Laid-Open No. 6-196204. If an insulating ring having such a configuration is used, there is no need to use a jig or the like for positioning at the time of glass joining, so that the above-described problem that the jig is fixed to the insulating ring or the solid electrolyte tube can be solved. Further, the reliability of the glass joint can be significantly improved.

However, since an insulating ring for a sodium-sulfur battery requires high dimensional accuracy, it is necessary to use
The upper and lower surfaces and the entire inner and outer diameter portions are polished and used. As in the case of the insulating ring shape described in JP-A-6-196204, it is not easy to polish the step on the inner diameter side at the stage of the sintered body. Further, since the first facing portion facing the opening end of the solid electrolyte tube does not face the entire opening end surface,
Stress concentrates on the end glass reservoir formed in this portion, and cracks generated in the glass reservoir are more likely to propagate to the solid electrolyte tube and lead to breakage. It was not enough.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a joint between an insulating ring and a solid electrolyte tube and a joint between an insulating ring and a metal member are each provided. Another object of the present invention is to provide an insulating ring shape capable of forming a joint having high reliability against thermal or mechanical stress, and a method of manufacturing the ring at low cost.

[0011]

According to a first aspect of the present invention, there is provided an outer peripheral surface near an open end of a bottomed cylindrical solid electrolyte tube and an upper end surface of an insulating ring which is glass-bonded to at least a part of the open end. The gist of the present invention is an insulating ring having a protrusion on at least a part of the lower end surface. The material of the insulation ring is
Those mainly composed of α-alumina are preferable in terms of insulation and cost.

In the present invention, the projections on the upper end surface and / or the lower end surface are provided as contact surfaces with the setter when the insulating ring is fired. It does not need to be on the circumferential side, and may be on the inner circumferential side of the upper end face or the outer circumferential side of the lower end face, respectively. When the protrusions are provided on both upper and lower end surfaces, any one of the protrusions on the upper and lower end surfaces may be set to the lower side, and firing may be performed in a state of being in contact with the setter.

In order to improve the roundness, a normal α-ring is fired by contacting one of the upper and lower end surfaces with a setter. However, due to friction with the setter due to firing shrinkage,
Since the surface roughness of the joint surface of the electrode metal member is deteriorated and the firing shrinkage ratio of the contact surface with the setter tends to decrease, there is a problem that the dimensional accuracy becomes insufficient. Therefore, when used as an insulating ring, the entire surface of the sintered body needs to be polished.

However, in the insulating ring of the present invention, by limiting the portion in contact with the firing jig (for example, the setter) only to the protrusion, the surface roughness of the bonding surface with the metal does not deteriorate, and Since the contact area with the sintered body is greatly reduced, the dimensional accuracy is greatly improved even with the sintered body before polishing, and the effect of eliminating the need for polishing is obtained.

According to a second aspect of the present invention, an L-shaped first member having an opening diameter larger than an outer diameter of an opening end of the solid electrolyte tube is formed on an inner peripheral surface on a lower end surface side of the insulating ring. The insulating ring according to claim 1, further comprising an insulating ring having a notch portion and a second notch portion having an opening diameter larger than an opening diameter of the first notch portion. Is an example.

The L-shaped first cutout portion having an opening diameter larger than the outer diameter of the opening end of the solid electrolyte tube is formed at least at a part of the opening end surface of the solid electrolyte tube and the outer peripheral surface in the vicinity thereof. Complementary to the above, the positioning of the solid electrolyte tube with respect to the insulating ring becomes easy, and the insulating ring and the solid electrolyte tube after glass bonding are kept concentric without using a jig or the like.

The second notch having an opening diameter larger than the opening diameter of the first notch includes an outer peripheral surface of the solid electrolyte tube formed by the first notch and an inner peripheral surface of the insulating ring. Is formed so as to form a gap wider than the gap between the first notch portion and the gap between the first notch portion and the solid electrolyte tube at the time of glass joining. Remains, so that strong bonding can be maintained.

The first cutout has an L-shaped cross section,
Complementary to at least a part of the open end surface of the solid electrolyte tube, it has a strong resistance to the stress generated in the longitudinal direction of the solid electrolyte tube, and greatly improves the reliability of the glass joint. Can be.

Usually, if complicated steps such as the first notch and the second notch are provided on the lower inner peripheral surface of the insulating ring, the polishing cost for the sintered body is greatly increased. Become. However, in the present invention, the protrusion is provided on the upper end surface and / or the upper and lower end surfaces of the insulating ring to reduce the contact resistance with the sintering setter, so that the dimensional accuracy of the sintered body is high and polishing is omitted. Is also possible, and the cost can be reduced as compared with the conventional case.

According to a third aspect of the present invention, there is provided an insulating ring wherein the axial length of the second notch is longer than the axial length of the first notch. It illustrates a more preferred configuration of the insulating ring described. With this configuration, stress concentration on the glass portion at the opening end surface can be reduced, and the reliability of the insulating ring joint can be improved.

In order to further improve the reliability of the joint portion of the insulating ring, it is effective to use an insulating ring in which the first cutout portion is complementary to the entire open end surface of the solid electrolyte tube and its outer peripheral surface. Since the first cut-out portion is complementary to the entire surface of the opening end surface of the solid electrolyte tube, stress concentration on the glass portion at the opening end surface can be further reduced, which is effective in further improving reliability.

Further, by increasing the axial length of the second notch, even if a material having a large volume shrinkage at the time of melting, such as a molded product of glass paste or powdered glass, can be used. Because enough bonding glass remains
A decrease in bonding strength can be prevented, which is effective in further improving reliability.

The insulating ring according to the present invention has an effect that the dimensional accuracy is high and the surface roughness of the bonding surface is not deteriorated because the bonding surface with the metal member does not contact the setter during firing. For this reason, it is also possible to arbitrarily adjust the surface roughness of the joint surface without polishing.

According to a fourth aspect of the present invention, the average surface roughness Ra of the upper end surface and the lower end surface of the insulating ring excluding the protrusion is 0.2 to 0.2.
The gist of the present invention is an insulating ring having a thickness of 1.0 μm, and illustrates a more preferable configuration of the insulating ring according to any one of claims 1 to 3. When the average surface roughness Ra of the upper end surface and the lower end surface excluding the protrusion is adjusted to 0.2 to 1.0 μm, the bondability with the electrode metal member becomes particularly strong, and the reliability of the bond between the insulating ring and the metal is improved. It is effective in improving the performance. A similar effect can be obtained by performing a polishing process as necessary and adjusting the surface roughness to the above-described one.

According to a fifth aspect of the present invention, there is provided a first step of forming an insulating ring molded body having a projection on at least a part of an upper end surface and / or a lower end surface of an insulating ring so that only the projection comes into contact with the first step. A second step of disposing the insulating ring molded body on a firing jig; and a third step of firing the insulating ring molded body in a state where only the protrusions are in contact with each other to form an insulating ring sintered body. The present invention provides a method of manufacturing an insulating ring according to any one of claims 1 to 4.

According to the present invention, firing is performed in a state where only the projections formed on the insulating ring molded body are in contact with the setter. Therefore, as described above, there is an effect that the dimensional accuracy of the sintered body is improved and the surface roughness of the joint surface is not deteriorated.

According to a sixth aspect of the present invention, the firing jig comprises a plate-like body and a columnar core material provided so as to be substantially perpendicular to the plate-like body. A step of loosely inserting the insulating ring molded body having the projection into the core material and disposing the molded body on the firing jig such that only the projection contacts the plate-like body; However, the insulating ring molded body is fired in a state in which only the protrusion contacts the plate-like body and at least a part of the inner surface of the insulating ring is in contact with the core material, and an insulating ring sintered body is formed. The gist is a method of manufacturing an insulating ring, which is a step of forming a ring.

In the present invention, the firing jig is composed of a plate-like body and a columnar core material provided substantially perpendicular to the plate-like body. The “plate-like body” referred to herein is a plate-like firing jig in a broad sense, and includes, for example, a setter. First, an insulating ring molded body having a protrusion is loosely inserted into the core material, and is placed on the firing jig such that only the protrusion contacts the plate-like body. Next, the insulating ring molded body is fired in a state where only the protrusion contacts the plate-like body and at least a part of the inner surface of the insulating ring contacts the core material. As a result, the insulating ring molded body grips the cylindrical core material with shrinkage during firing, so that the inner surface of the insulating ring is corrected by the outer peripheral surface of the core material. Further, since only the protrusions formed on the upper end surface or the lower end surface of the insulating ring molded body are fired in a state of being grounded to the setter, the surface roughness of the joint surface does not deteriorate.

The gist of the invention of claim 7 is a gist of a method of manufacturing an insulating ring in which a cylindrical core material satisfies the following (a) to (c). (A) The outer diameter of the core material at the maximum sintering temperature is equal to or larger than the inner diameter of the insulating ring. (B) The thermal expansion coefficient of the core material is larger than the thermal expansion coefficient of the insulating ring. (C) The core material is solid or cylindrical.

Using the core material having the above-mentioned constitutions (a) and (b), sintering is performed with only the protrusions formed on the upper end surface or lower end surface of the insulating ring molded body being in contact with the surface of the firing jig. As a result, at the maximum sintering temperature, the gap between the inner diameter portion of the insulating ring sintered body and the outer peripheral surface of the core material disposed therein substantially disappears, and the outer peripheral surface of the core material performs a correcting action. The dimensional accuracy of the unit is further improved. After the firing, a gap is generated between the inner diameter portion of the insulating ring sintered body and the outer peripheral surface of the core material disposed therein due to a difference in thermal expansion, so that the insulating ring sintered body can be easily removed from the core material.

Also, even when the outer diameter of the core material at the maximum sintering temperature is larger than the inner diameter of the insulating ring molded body at the time of sintering shrinkage, the insulating ring sintered body may be a sintering aid or the like. By the component (1), plastic deformation can be performed, and a sintered body with high dimensional accuracy corrected on the outer peripheral surface of the core material can be obtained. At this time, since the thermal expansion coefficient of the core material is larger than that of the insulating ring sintered body, the ring does not break or adhere to the core material even when cooled.

The core material is, as described in the above (c),
It is preferably solid or cylindrical. When firing a large insulating ring, it is particularly preferable that the insulating ring be cylindrical.
This is because the tubular member can significantly reduce the weight of the core material itself.

According to the invention of claim 8, the material of the insulating ring is α.
The gist of the present invention is a method of manufacturing an insulating ring made of alumina, wherein the core material is made of either magnesia or stabilized zirconia. The material of the insulating ring is preferably composed mainly of α-alumina from the viewpoint of insulating properties and cost, and the material of the core material is preferably composed of magnesia or stabilized zirconia having a larger coefficient of thermal expansion than alumina. It is necessary that the core material does not deform itself at the sintering temperature of the insulating ring and has low chemical reactivity. Therefore, a dense ceramic sintered body (relative density 98
% Or more).

[0034]

(Embodiment 1) An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 2 and FIG. 3 are cross-sectional views of the glass joint between the insulating ring of the present invention and the solid electrolyte tube. These insulating rings are provided with circumferential projections on the outer peripheral surface side and inner peripheral surface side of the ring upper surface, respectively, and a first cutout portion complementary to the open end outer peripheral surface side of the solid electrolyte tube. A second opening having an opening diameter larger than the opening diameter of the first notch.
Notches.

The first notch and the second notch are joined to a part of the opening end surface of the solid electrolyte tube and the outer peripheral surface in the vicinity thereof through the joining glass. here,
The compact of the bonded glass powder is inserted into the gap between the second notch and the solid electrolyte tube, heat-treated to melt the glass, and filled into the gap with the first notch.

In the conventional example shown in FIG. 12, the outer peripheral surface of the solid electrolyte tube and the inner peripheral surface of the insulating ring are glass-bonded. It is impossible to join to a certain position with
In the embodiment shown in FIGS. 2 and 3, since the positioning is performed by the first cutout portion having an L-shaped cross section, the use of a jig or the like is not required, and simple manufacturing is possible.

Further, the projections provided on the upper surface of the ring facilitate positioning of the metal member to be joined to the insulating ring. Even after the joining of the metal members, each of the solid electrolyte tube, the insulating ring, and the metal member can be positioned. Is no longer eccentric, and the solid electrolyte tube-insulating ring joint and insulating ring-
There is no variation in the joining strength of each metal member joint,
The reliability of the two junctions in a sodium-sulfur battery or the like is greatly improved.

Further, the area of contact with the setter at the time of firing the insulating ring can be reduced by this projection, so that the dimensional accuracy can be improved and the surface roughness of the joint surface with the metal member can be prevented from being deteriorated. This eliminates the need for polishing after sintering, and greatly contributes to cost reduction.

FIGS. 4 and 5 show other embodiments of the insulating ring. These are different in that the projections are located on the upper and lower surfaces of the ring. With this configuration, the surface that contacts the firing jig can be arbitrarily selected as needed.

Although not shown, each corner of the insulating ring is preferably chamfered with C or R. If polishing is not performed after firing, the chamfered portion is formed at the stage of the molded body. It is necessary to provide.

(Embodiment 2) An embodiment that embodies claim 3 will be described in detail with reference to the drawings.

FIGS. 6 and 7 are sectional views of a glass joint between the insulating ring and the solid electrolyte tube according to the third embodiment. These insulating rings are provided with circumferential protrusions on the upper end surface or lower end surface of the ring, a first cutout portion complementary to the entire open end surface of the solid electrolyte tube and its outer peripheral surface side, A second notch having an opening diameter larger than the opening diameter of the notch.

Since the length of the second notch in the axial direction is longer than that of the first notch, the volume shrinkage at the time of melting, such as a molded product of glass paste or powdered glass, is reduced. Even if a large material is used, a sufficient bonding glass remains in the second cutout portion, so that a reduction or variation in bonding strength can be prevented. Further, since the first notch portion is complementary to the entire surface of the opening end surface of the solid electrolyte tube, stress is not concentrated on the glass portion of the opening end surface, which is effective in further improving reliability.

(Example 3) As an example that embodies claim 4, a change in bonding strength with a metal member when the surface roughness of α-alumina was changed was evaluated.

An Al—Mn alloy plate of 24 mm square × 0.5 mm thick is placed between two cubes made of α-alumina each having a side of 24 mm and having a surface roughness (Ra) changed as shown in Table 1. 24mm □ × 0.1mm thick Al (92
%)-Si (7%)-Mg (1%)
This assembly was set on a hot press capable of controlling the atmosphere. These samples were heated to 570 ° C. in a vacuum of 1 Pa, and joined at this temperature under a pressure of 5 MPa for 60 minutes. The obtained joined body was processed into nine 6 mm × 48 mm square test pieces having a joined portion at the center in the longitudinal direction.

The strength of each of the nine bonded bodies obtained under each condition was measured in accordance with JIS-R1624 (bending strength test for ceramics bonding), and the relationship between the surface roughness of alumina and the bonding strength was investigated. As a result, in the sample of Ra = 0.2 to 1.0 μm which is within the scope of the present invention, the fracture in the bonding strength test occurred in the base material of alumina, but in the sample outside the range, the fracture occurred at the interface. did. For this reason, when the bonding surfaces of the upper and lower surfaces of the insulating ring with the metal are adjusted to the range of Ra = 0.2 to 1.0 μm, the improvement of the bonding strength is recognized, and it is understood that it contributes to the improvement of the reliability of the battery.

Here, the surface roughness was adjusted by changing the grinding conditions of alumina. However, in the case of an insulating ring having a product shape, the surface roughness of a molding die was adjusted to polish the sintered body. It is desirable to adjust the surface roughness of the sintered body without performing the above-mentioned steps, or to adjust the surface roughness within the above range by polishing the joint surface after sintering.

[0049]

[Table 1]

Example 4 In order to show the superiority of the insulating ring manufacturing method according to claims 5 to 8, the dimensional accuracy of the insulating ring during firing was evaluated.

The insulating ring was made of an alumina material and tested by the following method. Α-alumina was used as a starting material, and MgO, CaO, and SiO ₂ were used as sintering aids. α-alumina is a raw material having a purity of 99.9%, MgO, Ca
For O and SiO _2, first-class reagents were used. α alumina, Mg
O, CaO, SiO ₂ 99.5%, respectively, 0.15
%, 0.15%, and 0.2%, and a predetermined amount was mixed with a binder and a water solvent to form a slurry, and the slurry was spray-dried to obtain a granulated powder.

The powder was molded into the following two shapes by molding. Molded product shape A: outer diameter 90 mm x inner diameter 63.6 mm x first
Notch inner diameter 72 mm x second notch inner diameter 75.6
mm × Height 18 mm A protrusion having a height of 2 mm and a width of 2 mm is formed on the outer peripheral side upper surface. Molded body shape B: outer diameter 90 mm × inner diameter 63.6 mm × first
Notch inner diameter 72 mm x second notch inner diameter 75.6
mm × Height 20mm Height 2mm high and 2mm wide projections are formed on the inner and lower side

As a result of a pre-baking test conducted by bringing only the protrusion into contact with the setter, the inner diameter of this cylindrical sintered body was 40 m
In m, the ratio before and after firing shrinkage (the inner diameter of the formed body / the inner diameter of the sintered body) was 1.200. The coefficient of thermal expansion is 80 × 10
⁻⁷ / ° C. (30 to 1000 ° C.).

FIGS. 8 and 9 show an example of a method for manufacturing an insulating ring according to the fifth aspect. In the comparative example, the lower surface portion (the surface having no protrusion) of the molded body having the shape A was fired by contacting the setter with the setter (not shown).

FIGS. 10 and 11 show an example of the method for manufacturing an insulating ring according to claim 6, wherein a magnesia sintered body (outer diameter 52.56 mm × height 20 mm) is placed inside an insulating ring molded body having a shape A. FIG. 4 is a diagram showing a state in which a core material having a thermal expansion coefficient of 135 × 10 ⁻⁷ / ° C.) is arranged. In the firing test shown in Table 2, a core material made of a stabilized zirconia sintered body (coefficient of thermal expansion 110 × 10 ⁻⁷ / ° C.) having an outer diameter of 52.78 mm × a height of 20 mm was also used. The outer diameter of these cores is formed slightly larger than the inner diameter of the ring when the ring contracts at the firing temperature.

A firing test of the insulating ring was performed under the above five conditions, and the results of the dimensional accuracy are summarized in Table 2. The evaluation method is as follows.
Then, the outer diameter of the insulating ring and the inner diameter of the first notch were evaluated at a pass rate satisfying the following conditions. Insulation ring outer diameter part: φ75.0 mm ± 0.2 mm First notch part inner diameter: φ60.0 mm ± 0.2 mm

[0057]

[Table 2]

As a result of the firing test, the dimensional accuracy of the α-alumina insulating ring fired by the method of the present invention was improved, and the acceptance rate was improved. In particular, when the core material is disposed inside the molded body, the dimensional accuracy is remarkably improved, and glass joining with the solid electrolyte tube can be performed without polishing the sintered body.

This is considered to be due to the fact that the inner peripheral surface of the insulating ring was brought into contact with the outer peripheral surface of the core material during firing shrinkage, so that the effect of improving the dimensional accuracy had a greater effect. In particular, when the material of the insulating ring is α-alumina, the core material is preferably a magnesia-based or stabilized zirconia-based ceramic sintered body from the viewpoint of its thermal expansion coefficient and reactivity.

[0060]

According to the present invention, it is possible to form a joint with a solid electrolyte tube having high reliability against thermal or mechanical stress. In addition, since a sintered body having high dimensional accuracy can be obtained by a simple method suitable for mass production, it is possible to omit the polishing step of the insulating ring sintered body, which can greatly contribute to cost reduction of the insulating ring. Things.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a structure of a sodium-sulfur battery.

FIG. 2 is an explanatory view showing a joint between the insulating ring of the present invention and a solid electrolyte tube.

FIG. 3 is an explanatory diagram showing a joint between the insulating ring of the present invention and a solid electrolyte tube.

FIG. 4 is an explanatory view showing a joint between the insulating ring of the present invention and a solid electrolyte tube.

FIG. 5 is an explanatory view showing a joint between the insulating ring of the present invention and a solid electrolyte tube.

FIG. 6 is an explanatory view showing a joint between the insulating ring of the present invention and a solid electrolyte tube.

FIG. 7 is an explanatory view showing a joint between the insulating ring of the present invention and a solid electrolyte tube.

FIG. 8 is an explanatory view showing a method for firing an insulating ring molded body according to the present invention.

FIG. 9 is an explanatory view showing a method for firing an insulating ring molded body according to the present invention.

FIG. 10 is an explanatory view showing a method for firing an insulating ring molded body according to the present invention.

FIG. 11 is an explanatory view showing a method for firing an insulating ring molded body according to the present invention.

FIG. 12 is an explanatory view showing a joint between a conventional insulating ring and a solid electrolyte tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid electrolyte tube 2 Conventional insulating ring 3 Joining glass 4 Cathode side metal member 5 Anode side metal member 6 Sodium 7 Sulfur 8 Cathode lid 9 Battery case 10 Cathode terminal 11 Insulation ring of the present invention 12 Projection 13 First cutout Part 14 Second cutout part 15 Insulating ring molded body 16 Projection of insulating ring molded body 17 Firing jig 18 Hollow core material

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoshi Iio 14-18 Takatsuji-cho, Mizuho-ku, Nagoya City, Aichi Japan F-term (reference) 5H029 AJ11 AJ14 AJ15 AK05 AL13 AM15 BJ02 CJ02 CJ04 CJ05 CJ30 DJ03 EJ05 EJ06 EJ08 HJ00 HJ04 HJ14

Claims (8)

[Claims] 1. An insulating ring which is glass-bonded to an outer peripheral surface near an open end of a bottomed cylindrical solid electrolyte tube and at least a part of the open end, wherein an upper end surface and / or a lower portion of the insulating ring are provided. An insulating ring having a projection on at least a part of an end face. 2. An L-shaped first cutout having an opening diameter larger than an outer diameter of an opening end of the solid electrolyte tube on an inner peripheral surface on a lower end surface side of the insulating ring; 2. The insulating ring according to claim 1, further comprising: a second notch having an opening diameter larger than an opening diameter of the first notch. 3. 3. The insulating ring according to claim 1, wherein the length of the second cutout in the axial direction is longer than the length of the first cutout in the axial direction. . 4. An average surface roughness Ra of an upper end surface and a lower end surface of the insulating ring excluding the protrusion is 0.2 to 1.0 μm.
The insulating ring according to any one of claims 1 to 3, wherein 5. A first step of forming an insulating ring molded body having a projection on at least a part of an upper end surface and / or a lower end surface of the insulating ring, and forming the insulating ring so that only the projection comes into contact. A second step of arranging the body on a firing jig; and a third step of firing the insulating ring molded body in a state where only the protrusions are in contact with each other to form an insulating ring sintered body. The method for manufacturing an insulating ring according to any one of claims 1 to 4, wherein: 6. The method for manufacturing an insulating ring according to claim 5, wherein the firing jig is a plate-like body, and a cylindrical core material is provided substantially perpendicular to the plate-like body. The second step is that the insulating ring molded body having the projection is loosely inserted into the core material and the firing jig is arranged so that only the projection contacts the plate-like body. The third step is a step in which only the protrusion contacts the plate-like body and at least a part of the inner surface of the insulating ring contacts the core material. A process of firing an insulating ring to form an insulating ring sintered body. 7. The method according to claim 1, wherein the columnar core material comprises:
The method according to claim 6, wherein (c) is satisfied. (A) The outer diameter of the core material at the maximum sintering temperature is equal to or larger than the inner diameter of the insulating ring. (B) The thermal expansion coefficient of the core material is larger than the thermal expansion coefficient of the insulating ring. (C) The core material is solid or cylindrical. 8. The insulating ring according to claim 6, wherein said insulating ring is made of α-alumina, and said core material is made of magnesia or stabilized zirconia. Manufacturing method.