JP2000058110A - Electrochemical cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solid electrolyte separator tube assembly for a high- temperature rechargeable electrochemical cell, and its manufacturing method. SOLUTION: A solid electrolyte separator tube 12 comprises a ceramic insulating ring 14 sealed in an open end of the tube 12. An outer metal sealing ring 16 and an inner metal sealing ring 18 are coupled to the insulating ring 14 so as to seal it. The inner sealing ring 18 is positioned longitudinally inward apart from a coupling part between the outer sealing ring 16 and the insulating ring 14. The coupling between the sealing rings 16, 18 and the insulating ring 14 is a thermocompression bonding. The coupling part between the inner sealing ring 18 and the insulating ring 14 has an edge part sealed by a glass layer, is protected from the internal environment of the tube and then exposed to the inside of the tube.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to an electrochemical cell. More particularly, the present invention relates to a solid electrolyte separator tube assembly for a high temperature rechargeable electrochemical cell and a method of manufacturing the assembly. The invention also relates to a subassembly for said assembly and to a high-temperature rechargeable electrochemical cell comprising said assembly.

According to one aspect of the present invention, there is provided a solid electrolyte separator tube assembly for a high temperature rechargeable electrochemical cell, the assembly comprising a solid electrolyte separator tube having a closed end and an open end. ,
An insulating ring made of ceramic electrically insulating material sealed to the open end of the tube, an outer metallic sealing ring sealingly connected to the insulating ring, and an outer sealing ring between the outer sealing ring and the insulating ring; An inner metallic sealing ring sealingly coupled to the insulating ring at a location longitudinally inwardly spaced from the coupling with respect to the length of the tube, the coupling between the sealing ring and the insulating ring; A thermo-compression connection, wherein the thermo-compression connection between the inner sealing ring and the insulating ring has an edge exposed to the interior of the tube at the open end of the tube; Is sealed by the glass layer and hermetically protected from the environment inside the tube.

[0003] An outer metallic sealing ring is sealingly coupled to the insulating ring at a location longitudinally outwardly spaced from the open end of the tube, and an inner sealing ring extends longitudinally from the open end of the tube. It can be sealingly coupled to the insulating ring at locations spaced inward in the direction.

The glass layer which seals and protects the exposed edges of the thermocompression bond may comprise ceramic particles dispersed therein, for example of ceramic material of the insulating ring. The size of the ceramic particles is from 0.5 to 20 μm, preferably from 2 to 10 μm, and the proportion can be constituted by 10 to 50%, preferably 20 to 40% of the sealing ring by mass. The tube will typically include a cell electrode, such as a cell cathode. The surface of the insulating ring to which the sealing rings are each thermocompressed can be metallized. However, preferably, the metal of the sealing ring can be selected to have a coefficient of thermal expansion that matches the coefficient of thermal expansion of the ceramic of the insulating ring, in which case metallization can be omitted. Conformity means that the coefficients of thermal expansion of the metal and ceramic differ by no more than 20% of the value of the coefficient of ceramic.
Preferably, it means that the difference is not more than 10% in a temperature range of 0 to 500 ° C.

Furthermore, the thermocompression connection between the outer sealing ring and the insulating ring can have an edge which is furthest away from the inner sealing ring and which is sealed and hermetically protected by the glass layer. . That edge of the joint between the outer sealing ring and the insulating ring is usually located in the electrode compartment of the hot electrochemical cell, such as the anode compartment. And
Protection is from the environment of the electrode. Each sealing ring, especially the outer sealing ring, is provided with a coating selected from FeCr alloy or niobium where it is thermocompressed to the insulating ring.

In accordance with another aspect of the present invention, there is provided a method of manufacturing a solid electrolyte separator tube assembly for a high temperature rechargeable electrochemical cell, the assembly comprising a solid electrolyte having a closed end and an open end. A separator tube, an insulating ring of ceramic electrically insulating material sealed to the open end of the tube, an outer metal sealing ring sealingly connected to the insulating ring, and an outer ring with respect to the length of the tube. An inner metal sealing ring sealingly coupled to the insulating ring at a location longitudinally inwardly spaced from a joint between the sealing ring and the insulating ring, the method comprising: Thermo-sealing the sealing ring to the inside, glass welding the open end of the tube to the insulating ring, and exposing the inside of the tube between the inner sealing ring and the insulating ring. The edges of the thermo-compression bond portion which comprises that sealingly closed with a glass layer.

The sealing of the edge of the thermocompression connection between the inner sealing ring and the insulating ring by means of a glass layer at the edge has a large particle size of 150 μm, preferably 1 to 9 μm.
This can be done by applying a coating formed from a 0 μm powdered glass paste and heating the coating to melt the powdered glass and form a glass layer.
It is optional whether the paste is first dried or left to dry. When the ceramic particles have to be dispersed in the glass layer, a paste containing ceramic particles, such as ceramic powder particles dispersed in the glass particles, can be used. The method comprises sealing the edge of the thermocompression bond of the outer sealing ring, separated from the inner sealing ring, by a glass layer at the edge, as well as coating the edge with a coating formed from a powdered glass paste. This can be done by heating the material to melt the powdered glass and form a glass layer. Again, it is optional whether the paste is first dried or left to dry. When said edge is sufficiently close to where the tube is glass welded to the insulating ring, the heat from the glass weld will melt each coating of powdered glass to form a glass layer that is bonded by the heat. Can act as follows. However, when the heat from the glass weld is insufficient to melt the glass particles, the paste coating for the edges of the sealing ring can be separately heated to melt the glass particles.

[0008] Assemblies of the type in question are commonly used in cells of the type having a molten alkali metal anode and a transition metal halide cathode. The alkali metal is usually sodium, outside the tube,
It can be electrochemically connected to a transition metal halide cathode active material inside the tube. More specifically, the transition metal halide cathode active material is formed of a porous, electrolyte permeable, electronically conductive, conventional cathode active material transition metal in the form of particulates or in the form of a thin layer. The cathode active material can be dispersed in a matrix, the alkali metal is conveniently the metal of the anode and the halide is conveniently the chloride, the tube is provided by a molten salt electrolyte such as an alkali metal aluminum halide electrolyte. Is electrochemically bound to the solid electrolyte. Transition metals are Fe, Ni, Cr, Co, M
The sealing ring may conveniently be made of one or more of n and Cu, and the sealing ring conveniently comprises a matrix and a transition metal that is the same as the transition metal of the cathode active material.

When the cathode active material is nickel chloride, the sealing ring can be nickel or a nickel alloy, where a coating of FeCr alloy or niobium is particularly useful. Moreover, the ceramic of the insulating ring is conveniently α-alumina, the tube is made of β-alumina or preferably β ″ -alumina, and in this case the ceramic particles mixed with the glass particles are: It can be α-alumina particles.

[0010] The present invention extends to subassemblies. The subassembly consists of an insulating ring made of a ceramic electrically insulating material, an outer metallic sealing ring sealingly connected to the insulating ring, and an axial connection from the connection between the outer sealing ring and the insulating ring. An inner metallic sealing ring sealingly coupled to the insulating ring at an internally spaced location, wherein the insulating ring is thermocompression bonded to the sealing ring and separated from other couplings. The edge of the part is sealed with a paste layer containing glass particles.

The present invention further extends to a high temperature rechargeable electrochemical cell comprising a cell housing, wherein the cell housing is connected to an electrode compartment inside the separator tube by a solid electrolyte separator tube having a closed end and an open end. And the electrode compartment inside the cell housing outside the separator tube. The cell includes electrodes in each of the aforementioned compartments, wherein the electrodes are separated from each other by a tube and electrochemically connected to each other by a tube, wherein the tube forms part of a separator tube assembly, Is
A tube, an insulating ring of ceramic electrically insulating material sealed to the open end of the tube, an outer metallic sealing ring sealingly connected to the insulating ring, an outer sealing ring and an insulating ring; An inner metallic sealing ring sealingly coupled to the insulating ring at a location longitudinally inwardly spaced with respect to the length of the tube from the joint between the sealing ring and the insulating ring. Is a thermo-compression connection, wherein the thermo-compression connection between the inner sealing ring and the insulating ring has an edge exposed inside the tube at the open end of the tube; The edges are sealed by a glass layer and hermetically protected from the interior environment of the tube, an outer sealing ring is coupled to the housing to seal the housing, and an inner sealing ring is sealed to seal the tube. It is.

[0012] The outer sealing ring can be connected to the housing by a closure such as a lid for the housing. The inner sealing ring can be closed by a closure, such as a lid for the tube.

[0013] The present invention extends to a solid electrolyte separator tube assembly for a high temperature rechargeable electrochemical cell.
The assembly includes a solid electrolyte separator tube having a closed end and an open end; an insulating ring made of a ceramic electrically insulating material sealed to the open end of the tube;
An outer metallic sealing ring sealingly joined to the insulating ring, and a longitudinally inwardly spaced position relative to the length of the tube from the junction between the outer sealing ring and the insulating ring to the insulating ring. An inner metal sealing ring sealingly connected, wherein a connection between the sealing ring and the insulating ring is a thermocompression bonding, wherein a thermocompression bonding between the inner sealing ring and the insulating ring is provided. The joint has an edge that is inside the open end of the tube and exposed to the inside of the tube, and a thermocompression joint between the outer sealing ring and the insulating ring,
An edge proximate the tube and outside the tube and exposed to the outside of the tube, at least one of the edges being hermetically sealed by the glass layer and hermetically protected from the surrounding environment.

In use, the assembly will typically form part of a high temperature rechargeable electrochemical cell having an alkali metal anode and a transition metal halide cathode.
Preferably, a layer of glass is exposed at the anode of the cell, which is usually in a tube having a cathode outside the tube.

The insulating ring is made of α-alumina,
It can be metallized or unmetallized. Preferably, the insulating ring is metallized, the sealing ring is made of nickel and a single glass layer is located inside the tube.

When the insulating ring is not metallized, the metallic sealing ring is made of Niro K or Niro 42 and can optionally be coated with a FeCr alloy or niobium. And two glass layers can be on the inside and outside of the tube respectively.

Next, the present invention will be described with reference to the accompanying drawings.
Will be described as an example.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, a solid electrolyte separator tube assembly according to the present invention is generally designated by the reference numeral 10, comprising a β "-alumina separator tube 12, an α-alumina insulating ring and 14, and an outer tube. A nickel or nickel alloy sealing ring 16 and an inner nickel or nickel alloy sealing ring 18. The insulating ring 14 can be metallized α-alumina or unmetallized α. It can also be alumina.

The insulating ring 14 is made of α-alumina and has a rectangular shape with a plane outline of 20 and rounded corners. Along its perimeter, on its lower side, a downward facing shoulder 24
Is provided. Tube 12
Has a closed end (not shown) and a rim,
It has an upper rectangular open end that fits into the rebate 22 and abuts the shoulder 24 and is glass welded in place. The tube is elongated and can have a rectangular horizontal cross-section along its length to its lower closed end, or tapered,
It can also converge to a cross-shaped cross section (not shown).

The ring 16 has an annular flange 26 that is thermocompression bonded to a flat annular upper surface 28 of the ring 14, and the flange 26 has a rim 30 that stands upright along its inner circumference. The ring 18 then has an annular flange 32 thermocompression bonded at 34 to the flat annular lower surface of the ring 14 and the ring 18 has a rim 36 standing upright along its inner circumference. The rim 36 abuts the curved surface of the circular central passage 38 via the ring 16.

A radially outer edge of the flange 32 of the ring 18, between this edge and the inner surface of the tube 12, a radially outer edge of the thermocompression connection between the flange 32 and the ring 14. Peripheral recess 4 partially filled with glass beads or fillets 41 (only shown on the right hand side of FIG. 1) forming a layer that seals and protects the edges
There is 0. Similarly, when the ring 14 is made of unmetallized alumina, the radially outer periphery of the flange 26 of the ring 16 is sealed and at 42 a protective layer (only shown on the right hand side of FIG. 1). Is protected by a glass bead 43 forming These glass beads are made of a paste of particles of glass powder, for example Schott.
Obtained by forming a paste of Glass No. 8245 grade glass particles, optionally containing α-alumina powder particles as a filler. The paste is dried and the glass in the dried paste is melted and
A somewhat continuous layer of protective glass is formed at 0 and 42 to seal and protect the radially outer edge or periphery of the joint between the flange 26 and the flange 32 and the ring 14. When both joints must be protected by glass at 40 and 42, such as when the ring 14 is made of unmetallized alumina, the glass used is the coefficient of thermal expansion of the metal of the rings 16 and 18. Should have a coefficient of thermal expansion that matches as accurately as possible. Therefore, metal /
The alumina interface is coated with a FeCr alloy or niobium to prevent or prevent sodium attack (since the ring 16 is made of unmetallized alumina). Because the rings 16, 18 are Nilo 4
2, or Niro K, because the coefficient of thermal expansion matches that of an unmetallized alumina ring.

If the ring 14 is made of metallized α-alumina, then the glass bead or fillet 43 can be omitted. Alternatively, simply protecting the metal-alumina interface at 42 with a layer of FeCr alloy or niobium can prevent or prevent sodium attack on the metal / alumina interface.

Preferably, a metallized alumina ring 14 is used, when the rings 16 and 18 are
Usually made of nickel.

In practice, in the rebate 22, the heat of glass welding the tube 12 to the ring 14 is sufficient to melt the glass particles in the dried paste at 40, but to form a sufficient protective glass layer. However, it has been found that if necessary, separate heating can be used to melt the glass particles in the 42 paste.

The advantages of the present invention are surprisingly 40 and 4
The use of glass beads in 2
Therefore, the strength of the thermocompression bonding portion between the ring 14 and the ring 14 is increased. In addition, the glass layers formed by the glass beads at 40 and 42 protect the joint from stress corrosion attack due to the adverse environment of the cell electrode that is exposed during use. Surprisingly, the metallization of the surface of the ring 14, where the rings 16 and 18 are joined, is such that
It has been found that, if used in and, it is not necessary for a good thermocompression bond.
Further, when the ring 14 is made of unmetallized alumina, if the rings 16 and 18 are made of a metal such as Niro 42 or Niro K that matches the coefficient of thermal expansion of the ring 14, the rings 16 and 18 are It has been found desirable to coat with a FeCr alloy or niobium.

[Brief description of the drawings]

FIG. 1 shows a partial side view of the solid electrolyte separator tube assembly according to the present invention, taken along line II of FIG.

FIG. 2 shows a plan view of the assembly of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Separator tube 14 Insulation ring 16, 18 Sealing ring 22 Rebate 24 Shoulder 26, 32 Flange 30, 36 Rim 38 Central passage 40, 42 Protective glass layer 41 Fillet 43 Glass bead

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Walter Giorgi Bagden Nottingham N.G.8.1 G.G., Wollaton, Cashmere Drive.9

Claims (13)

[Claims] 1. A solid electrolyte separator tube assembly for a high temperature rechargeable electrochemical cell, comprising: a solid electrolyte separator tube having a closed end and an open end; and a ceramic sealed to the open end of the tube. An insulating ring made of an electrically insulating material, an outer metallic sealing ring sealingly connected to the insulating ring, and a longitudinally inner side with respect to the length of the tube from the connection between the outer sealing ring and the insulating ring. An inner metal sealing ring sealingly coupled to the insulating ring at spaced apart locations,
The joint between the sealing ring and the insulating ring is a thermo-compression connection, and the thermo-compression connection between the inner sealing ring and the insulating ring has an edge exposed inside the tube at the open end of the tube. An assembly having said exposed edge sealed by a glass layer and hermetically protected from the environment inside the tube. 2. An outer metal sealing ring is sealingly coupled to the insulating ring at a location longitudinally outwardly spaced from the open end of the tube, the inner sealing ring being connected to the open end of the tube. 2. The assembly of claim 1, wherein the assembly is coupled to the insulating ring at a location longitudinally inward from the insulation ring. 3. An assembly according to claim 1, wherein the glass layer sealing and protecting the exposed edges of the thermocompression bond comprises ceramic particles dispersed therein. 4. The assembly according to claim 1, wherein the metal of the sealing ring is selected to have a coefficient of thermal expansion matching the coefficient of thermal expansion of the ceramic of the insulating ring. 5. The thermo-compression connection between the outer sealing ring and the insulating ring has an edge which is furthest from the inner sealing ring and sealed and hermetically protected by the glass layer. An assembly according to any one of claims 1 to 4. 6. The assembly according to claim 1, wherein each sealing ring is provided with a coating selected from a FeCr alloy or niobium where each sealing ring is thermocompression-bonded to an insulating ring. 7. A method of manufacturing a solid electrolyte separator tube assembly for a high temperature rechargeable electrochemical cell, the assembly comprising a solid electrolyte separator tube having a closed end and an open end, and an open end of the tube. An insulating ring made of a ceramic electrical insulating material sealed to the outer ring, an outer metallic sealing ring sealingly connected to the insulating ring, and a gap between the outer sealing ring and the insulating ring with respect to the length of the tube. An inner metallic sealing ring sealingly coupled to the insulating ring at a location longitudinally inward from the coupling, the method comprising thermocompression sealing the sealing ring to the insulating ring; Glass welding the open end of the tube to the insulating ring, and glass the edge of the thermocompression bond exposed inside the tube between the inner sealing ring and the insulating ring A method comprising hermetically sealing with a layer. 8. A coating formed from a paste of powdered glass is applied to the edge of the thermocompression connection between the inner sealing ring and the insulating ring, and the coating is heated to melt the powdered glass. 8. The method according to claim 7, wherein the edge is sealed by a glass layer by forming a glass layer. 9. The sealing of the edge of the thermo-compression connection of the outer sealing ring, separated from the inner sealing ring, by a glass layer on the edge, applying a coating formed from a paste of powdered glass to said edge. 9. The method according to claim 7 or 8, comprising heating the powder to melt the powdered glass to form a glass layer. 10. The method according to claim 8, wherein the heat from the glass welding acts to melt the respective coatings of the powdered glass to form a bonded glass layer. 11. A subassembly for a solid electrolyte separator tube assembly, comprising: an insulating ring made of a ceramic electrically insulating material; an outer metallic sealing ring sealingly coupled to the insulating ring; An inner metallic sealing ring sealingly coupled to the insulating ring at a location axially inwardly spaced from a joint between the sealing ring and the insulating ring, wherein the insulating ring heats the sealing ring. A subassembly in which the edges of each joint crimped and separated from other joints are sealed with a paste layer containing glass particles. 12. A high temperature rechargeable electrochemical cell comprising a cell housing, the cell housing being defined by a solid electrolyte separator tube having a closed end and an open end, an electrode compartment inside the separator tube, and a separator. Dividing the cell into electrode compartments inside the cell housing outside the tube, the cell including electrodes in each of the aforementioned compartments, wherein the electrodes are separated from each other by a tube and electrochemically connected to each other by a tube; Forms part of the separator tube assembly,
The separator tube assembly comprises a tube, an insulating ring of ceramic electrically insulating material sealed to the open end of the tube, an outer metallic sealing ring sealingly coupled to the insulating ring, and an outer metal sealing ring. An inner metallic sealing ring sealingly coupled to the insulating ring at a location longitudinally inwardly spaced with respect to the length of the tube from the junction between the sealing ring and the insulating ring, the sealing ring comprising: The connection between the and the insulating ring is a thermocompression connection, the thermocompression connection between the inner sealing ring and the insulation ring,
At the open end of the tube there is an exposed edge inside the tube, said exposed edge being sealed by a glass layer and sealingly protected from the interior environment of the tube, and an outer sealing ring for the housing. A cell coupled to the housing for closing and the inner sealing ring is closed to close the tube. 13. A solid electrolyte separator tube assembly for a high temperature rechargeable electrochemical cell, comprising: a solid electrolyte separator tube having a closed end and an open end; and a ceramic sealed to the open end of the tube. An insulating ring made of an electrically insulating material, an outer metallic sealing ring sealingly connected to the insulating ring, and a longitudinally inner side with respect to the length of the tube from the connection between the outer sealing ring and the insulating ring. An inner metallic sealing ring sealingly coupled to the insulating ring at spaced locations,
The connection between the sealing ring and the insulating ring is a thermo-compression connection, and the thermo-compression connection between the inner sealing ring and the insulation ring is inside the open end of the tube and inside the tube. Having an exposed edge, wherein a thermocompression connection between the outer sealing ring and the insulating ring is near the tube and outside the tube and has an edge exposed outside the tube;
An assembly wherein at least one of said edges is sealed by a layer of glass and hermetically protected from the surrounding environment.