JPH05177619A - Preparation of holder made of ceramic material and holder - Google Patents

Abstract

PURPOSE: To manufacture a holder efficiently by solidifying a ceramic particulate material with an embedded core inside, removing the core to form a green artifact having cavities inside, and sintering the green artifact to produce a sintered single artifact. CONSTITUTION: An apparatus 10 is constituted of a mold or die body 12 and a pair of mobile die plungers 14, 16. A premixed particulate mixture 18 of, for example, β-alumina particles and wax is injected into inside of the die body 12 and a core is embedded with many passages 22 inside the particulate mixture 18. One mobile die plunger 14 is pressed against the other mobile die plunger 16 to compress the particulate mixture 18 around the core 20 and inside the passages 22. Then the other mobile die plunger 16 is drawn out to the reverse side and the compressed green artifact 30 containing the core 20 is taken out of the die body. After that, the green artifact 30 is sintered to produce a sintered single artifact.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of manufacturing a holder made of a ceramic material. More particularly, the present invention relates to a method suitable for making a holder made of a ceramic solid electrolyte material holding an active electrolyte material in a high temperature rechargeable electrochemical storage battery, and a holder made by this method.

[0002]

SUMMARY OF THE INVENTION The present invention is a method of making a holder made of a solid ceramic material, wherein at least one core is placed within a mass of granular ceramic material or its granular precursor material, and the core is surrounded by each core. The granular material is compressed and solidified so that the cores are at least partially embedded within the granular material and each core is removed from the solidified mass of granular material, leaving a green workpiece with cavities inside. And sintering the green workpiece to create a sintered single workpiece of a ceramic material having at least one cavity for the final contents of the holder to contain, the particulate material comprising: Each core is formed such that at least a portion of each core is arranged in the shape of a thin slab or layer sandwiched between a pair of layers of granular material, and after sintering at least a portion of each cavity. Part Each slab or layer has at least one through-opening through which granular material is filled, in the form of a thin gap between opposed plates of sintered ceramic material. The material is compressed to solidify the granular material in the gap and, after sintering, forms a bridge across the gap between the connected plates,
Sintered into the bridge, the bridge acts as a support or tie between the connecting plates, providing a method by which the holder can be strengthened.

By thin gap is meant a gap with a thickness of up to 10 mm, for example 0.2-6 mm, typically 1-5 mm.

The "precursor material" of a granular ceramic material is
By granular material which is transformed or converted into a ceramic material for the holder when heated in the sintering step. The particle size of the granular ceramic material or its precursor is 10-2.
00 μm, 20-50 μm for isotropic compression
An average particle size of m is preferred, while for die or uniaxial compression an average particle size of 50-100 μm is preferred.

Each slab or layer may have a plurality of apertures therethrough, the apertures being spaced apart from one another, so that after sintering the plates are joined by a matrix of bridges spaced apart from one another. Each opening may be shaped so that the bridges are in the form of short cylinders or columns evenly spaced from each other and distributed throughout the gap. Preferably, each core consists of at least one single slab, each opening being shaped such that its side cross section is in the shape of a passage with a radially inwardly convexly curved wall. There are a pair of inlets at each opposite end, each inlet being dish-shaped. Therefore, it is tapered inwardly of the passage in the axial direction. Each slab may be convexly curved and have a rounded peripheral edge. This provides a generally hourglass-shaped cylinder or column of solidified material with rounded edges that join the layers or plates, and ultimately a sintered tether or knot. These rounded slabs and rounded edges are resistant to cracking when the sintered workpiece is stressed.

The ceramic material may be a solid electrolyte material for holding the active electrode material of a high temperature electrochemical cell. Each core is completely surrounded by the granular material, which after compression is completely embedded in the solidified granular material and is sintered to obtain a work piece having closed cavities therein. The method further includes forming a feed opening from outside the holder into the cavity after sintering.

In this case, the workpiece cavity can remain closed until it is filled with the active electrode material. Thus, the openings, preferably for filling or dispensing the active electrode material, may optionally be machined into the cavity immediately prior to dispensing the active electrode material. This keeps the surface of the work piece exposed in the cavity clean and pure and prolongs the shelf life of the work piece. This may be important if the active electrode material is a molten alkali metal such as sodium. Of course, instead, the core may have protrusions through the granular material. Removal of the core creates feedthroughs or feed openings. In this case, when removing the core by heating, instead of having to penetrate the particulate matter as occurs with the cavity still closed, the molten core material is heated to a temperature slightly above its melting point, for example 50 ° C.
Can flow out through the opening.

When it is necessary to retain a solid electrolyte material, the holder is compressed into a pressed or flat shape. For example, joined at their edges,
A laterally flat envelope having a pair of opposite outwardly facing major surfaces, at least one of its cavities being near at least one of the major surfaces of the holder.

The compression or solidification of the granular material is carried out by placing the core in the mass of the granular material in a mold and then isostatically or uniaxially (die) or uniaxially and then isostatically compressing. Can be implemented. The uniaxial compression step may be performed and the isotropic compression step may be performed at about the same time for compression. When solidified, a green processed product surrounding the core is manufactured,
The workpiece must be strong enough to maintain its integrity during subsequent core removal and sintering. The compression is from below room temperature to a high temperature, for example 35-500 ° C, pressure 30-31.
It can be carried out at 0 MPa, preferably 30-150 MPa. In order to obtain good green density and green strength in green products, the method may include the step of mixing a suitable binder with the particulate material before placing the core in the particulate material. The binder can act as a lubricant to lubricate the compacts, suitable binders including, for example, polymers or waxes soluble in aqueous or organic solvents.
For example, polyvinyl butyrate, polyvinyl acetate,
Included are polyvinyl alcohol, polyethylene glycol, polyethylene oxide and polymers, waxes or binders known in the art. These binders may form 0.5-30% by weight of the mixture of binders and the electrolyte / precursor material may suitably form 0.5-15% by weight.

In a particular embodiment of the invention, the compression is -20 ° C.
It may be carried out at a temperature of ˜ + 500 ° C. and a pressure of 30-310 MPa. The method includes the step of mixing 0.5-30% by weight of an organic binder with the particulate material prior to placing each core in the particulate material, and sintering serves to remove the binder out. have.

The core is generally removed by heating in air. The core is therefore a temporary, sacrificial material that is removed by melting, sublimation (optionally under vacuum), vaporization and / or combustion / oxidation within the first stage of heating used, for example, in the sintering of green workpieces. Can be formed. Although a core is used that is shaped to provide a cavity of the desired shape, the core can of course be shaped to provide an opening or inlet / outlet leading to the cavity from outside the holder. The temporary substances include the above-mentioned binder and carbon or graphite foil, sheet, slab or block, ashless paper, naphthalene, wax, etc., and especially ice can be used as the temporary substance. In this case, it is naturally possible to melt / evaporate as desired, but it is preferable to remove it by sublimation. In certain embodiments, the core may be a mixture of a fugitive substance and a sinterable ceramic or precursor material thereof, such as the ceramic solid electrolyte itself or precursor material thereof. In this case, in order to increase the strength of the sintered product, the inside of the cavity can be made porous and liquid permeable.

[0012] Preferably, when using a core that sublimes under vacuum and can be condensed and recovered for reuse, the binder is the same material as the core. However, when the core material is different from the binder, it is preferable to remove the core material first and leave the binder as it is to obtain a stronger green processed product upon sintering, for example by subliming ice to obtain a higher melting point. Leave high binder in place.

If the ceramic workpiece is a flat shape and the core is a slab, the compression and solidification of the particulate material can be done by uniaxial or die compression in a metal die. However, if a more complex ceramic work piece is required, for example in the form of a hollow column with several intermediate flat envelopes at regular intervals along the length, it is possible. It is preferable to compress and solidify using isotropic compression using a flexible bag or sheath. In this case, a pillar type core can be used. This core has a plurality of slabs at regular intervals in the longitudinal direction, and the slab has a shape of a flange or a fin protruding from a column,
It extends like a disk in the circumferential direction and projects outward in the radius direction. The granular material can then be packed around the core within the sheath prior to isotropic compression. The solidified material is
A contoured sheath mated with the fins or flanges of the core can be used that is machined and then sintered and / or circumferentially stretched to obtain the required profile, if desired. The core may be a one-piece solid, which may be formed, for example, by casting, or it may be a composite of the type formed from annular disk stacks spaced by annular spacers of smaller diameter than the disks. They can also be passed through a metal rod which can be removed during wax removal, eg after compression. The disc forms fins or ribs,
The spacer forms a pillar. In each example, the fin may have a through opening for receiving the particulate material from the support or tether portion after sintering, which preferably has an hourglass-shaped cross section as described above.

In another embodiment of the invention, the core may be hollow cylindrical and has radially arranged through openings for support or tethering. Again, this can be compressed, for example, by isotropic compression using a flexible sheath or bag of latex, the core being radially outward from the mandrel around the mandrel and the granular material, on the one hand, between the mandrel and the core. Filled between, and on the other hand, between the core and the sheath, the sheath being located radially outwardly and radially outward from the core.

If the holder is to be used for connection to a reservoir of active electrode material, for example a molten sodium reservoir, one cavity of at least one in the holder, which is thin and has a small volume, for example the thin gap described above, is used. Can be formed near one surface. However, if the holder is not intended to be used to connect the anode material to the reservoir, it is also possible to form such a reservoir separately in another cavity, which may have a larger volume.

Thus, the method of the present invention can use, for example, two, usually three, cores embedded in a granular material to provide 2-3 cavities in a sintered workpiece. One of the cores is thick and provides a reservoir, the other is thin and to provide an electrode space near the surface of the workpiece to enhance ionic conduction. Two cores are used when the work piece has a reservoir of active electrode material and is intended for use in a battery having this work piece on one side of the other active electrode material of an electrochemical cell. Three cores are used if the workpiece has a reservoir of active electrode material and is intended for use in a battery that is sandwiched between two electrode portions of another active electrode material of an electrochemical cell. When using three cores, place the thick core in the middle and the two thin smaller cores on either side of the middle core.

Thus, there may be two opposed cores in the form of slabs which are face-to-face separated by a layer of granular material, the cores having different thicknesses. There may also be three opposing cores in the form of slabs, each facing away from each other by two layers of granular material,
The central core is located between the two outer cores at a constant distance from the outer cores, the central core being thicker than the outer cores.

Thus, when the workpiece is a flat shape, the core may be flat and face-to-face spaced apart in the die with a flat layer of granular material sandwiched therebetween. When the work piece is a hollow cylinder, the core may be concentrically spaced between the central mandrel and the outer sheath with a layer of particulate material sandwiched therebetween. The cores can also be spaced with spacers of core material. The spacer can be removed with the core from the solidified mass of particulate material. After that, there will be a liquid flow duct connecting the cavities formed after the core.

Thus, when the core is in a granular ceramic material, at least one spacer of the core material can separate the thick core from each of the other cores, each spacer becoming a duct in the workpiece after sintering, You can connect cavities made of thick cores to other cavities.

At least one core may be provided with particles of a wicking substance or precursor material thereof, at least on the surface of the core or in a portion embedded in the core material, and by sintering, of the cavity formed by the core. At least on the inner surface, a porous wicking material is provided that wicks the final contents of the holder in liquid form.

When there is thus one core, it is possible to form a core having a surface layer containing particles of the wicking material or its precursor material embedded in the core material. Upon removal of the core material, this thin layer provides a porous wall surface for the cavity formed by the core into which the active electrode material, eg molten sodium, is wicked up by capillarity. Where there are several evenly spaced cores, each smaller core contains particles of such wicking material throughout its core, and thus the voids remaining after removal of such small cores are porous. Can be filled with wicking material.

As noted above, an important application for the sintered ceramic workpieces made by the method of the present invention is as electrode holders in high temperature rechargeable electrochemical cells, usually molten alkali metal anode holders. In this case, the solid electrolyte material or precursor material used is selected to provide a ceramic workpiece which is a conductor of the alkali metal ion of interest. Sodium / sulfur type cells, or cells consisting of a molten sodium anode and a transition metal halide active cathode dispersed in a porous permeable conducting material matrix impregnated with an alkali metal haloaluminate molten salt electrolyte The electrolyte material of the product is NASICON, β
-Alumina, or preferably β "-alumina.

Suitable ceramic solid electrolytes also include analogs of β- or β "-alumina, where the sodium ions of β- or β" -alumina are at least partially replaced by other metal ions. And thus (in batteries where the anode is such other metal) the ceramic is a conductor of such other metal ions.

When the holder is a solid electrolyte ceramic material, it can be used in a high temperature rechargeable electrochemical storage battery consisting of a pair of electrodes, an anode and a cathode and a holder. Here, one of the electrodes is held in a holder, the wall of the holder acts as a solid electrolyte separator between the anode and the cathode, and the solid electrolyte separator is the conductor of the active anode material ions of the battery. ..

Further, such a solid electrolyte holder can provide an electrode structure, for example, an anode structure, to the battery when holding the electrode material of the battery.

Preferably, the electrode carried by the holder is an anode and the active anode material is generally a metal such as an alkali metal such as sodium (when the ceramic solid electrolyte material is Nasicon, β-alumina or β ″ -alumina). is there.

The present invention also includes a holder made of a ceramic solid electrolyte material as long as it is produced by the method of the present invention.

[0028]

EXAMPLES Examples will now be illustrated with reference to the following illustrative examples and diagrams.

In FIG. 1, reference numeral 10 generally designates a mold and die arrangement during uniaxial compression of a holder in the form of a transverse flat envelope which is compressed in the method of the present invention. The apparatus 10 comprises a mold or die body 12, a movable die plunger 14 and a movable die plunger 16.

Inside the mold is shown a mass 18 of granular β "-alumina particles having an average particle size of 50-100 μm, mixed with 15% by weight of a water-soluble wax or polyethylene glycol. Embedded in a core 20, which is a cast of polyethylene glycol (see also FIG. 2 where the core is designated 20).

With reference to FIG. 2, a flat rectangular or slab-shaped core 20 has a plurality of tubular openings uniformly distributed over its entire surface, interconnecting major surfaces 24, and extending through the core 20. There are 22.

According to the method of the present invention, the device 10 is assembled with the plunger 14 retracted and the plunger 16 in place, as shown in FIG. A granular mixture of β-alumina particles 18 and wax, premixed as described below, is placed inside the mold and the preformed core 20 is embedded in the mixture 18, as shown. This involves placing a substantially flat layer of about half of the mixture 18 inside the mold, placing the core 20 on that layer, and placing the rest of the mixture 18 on the core 20 in the mold as a second flat layer. , Hole 22 and core 2
It is carried out by also filling the peripheral space between 0 and the wall of the mold or die body. The plunger 14 is then uniaxially pushed in the direction of arrow 26 towards the plunger 16, which acts as an anvil, compressing the mixture around the core 20 and in the tube 22. The plunger 16 is then retracted in the opposite direction and the manufactured green workpiece 30 containing the core 20 is removed from the mold 12.

Next, the green processed product is heated in air, an inert gas or under vacuum to a temperature of up to 500 ° C., for example 400 ° C., to remove polyethylene glycol. next,
The green work is further heated to evaporate the free water or surface bound or chemically bound water in the mixture first, then the β ″ -alumina particles are sintered together second, a single continuous sintering Form a polycrystalline β ″ -alumina workpiece.

The work piece is a flat shaped envelope having a flat internal cavity in the form of a gap opened by the core 20. The β ″ -alumina in the holes 22 is sintered into pillars that integrate with, strengthen, and separate from the major surface of the envelope formed from layers of the mixture 18 on either side of the core 20 in the mold 12. These major aspects are core 20
The mixture 18 injected into the peripheral space between the edge of the mold and the mold 12.
Are bound around the envelope by.

In this regard, the core 20 (FIG. 2)
A knob or ear 28 in the middle along one of its lateral edges
It has an outward projection in the form of. The core is placed in the mold so that the ears 28 contact the mold wall at location 30 (FIG. 1). After the core is removed and sintered, the ears 28 leave a space through the lateral edge that forms a feedthrough or feed opening to the inner cavity of the envelope from which the core 20 opens from the outside of the envelope.

In contrast, in FIG. 3, there is no ear 28, and instead there is a pair of truncated cylindrical projections 32, each of which is located in the center of the opposing surface of the core on the major surface thereof. One is shown in FIG. The core of FIG.
And the plunger 16 and the anvil 16 are kept free of the mixed substance 18. After removing the core and sintering,
From the space created by these projections, an envelope is obtained that has a pair of opposed central openings that pass through the major surface of the envelope wall.

In FIG. 4, the same reference numerals indicate the same parts as in FIG. 1, unless otherwise specified. The apparatus shown in FIG. 4 is for the core 20 of FIG. 3 to create an envelope or holder for the same purpose. However, in the case of FIG.
There is no protrusion 32 on the core 20 of FIG. 3 and a rod 34 is used. Plungers 14, 16 each have a central opening or passage 36, 38 within which is a rod 34. Similar to the protrusion 32 of FIG. 3, the rod 32 provides an envelope with a central opening that opposes through the major surface of the envelope wall.

FIGS. 5-8 show various cores 20 used for isotropically compressing a holder or envelope. These are somewhat complex shapes except for FIG. 7, which can also be made with uniaxial or die compression. Thus, in FIG. 5, the core 20 has a star-shaped cross section, and has a plurality of slab-shaped wings 40 extending outward at equal intervals on the circumference. Each has a hole 22 similar to the holes of FIGS. 1-4. During compression of the corresponding holder or envelope, this core is embedded in a latex bag (not shown) having an interior with a shape and cross section similar to that of core 20, and thus a mass of particles (see FIG. 18) of 1 forms a layer of approximately uniform thickness between the core 20 and the latex bag. The particles fill the holes 22. The core has a cylindrical central protrusion 42 at one end, forming an opening at one end toward the hollow interior of the final holder or envelope.

The core 20 of FIG. 6 is generally similar to the core of FIG. 5, and like reference numbers refer to like parts. The major difference is that there are only two wings 40 each having a U-shaped cross section and the entire holder has a substantially S- or Z-shaped cross section.

In FIG. 7, a core 2 similar to the core 20 of FIG.
0 is shown, but a cylindrical protrusion 42 is used in place of the knob or ear 28 of FIG. Figure 8 on one side
Shows a modification of the core of FIG. The core 20 of FIG. 8 is relatively wide and short, and has a thick cylindrical portion 4 at one end.
Have 4. There is no hole 22 in this part, which in use forms an expanded part inside the holder and acts as an upper reservoir in the holder or envelope for the active electrode material. The protrusion 42 vertically projects outside the portion 44.

Of course, like the core of FIG. 5, the core of FIGS. 6-8 is used with a latex bag of suitable complementary shape for isotropic compression of particles. In each case the particle agglomerates are arranged as a layer between the core and the corresponding latex bag, forming an envelope or holder. Holders of other shapes can be similarly created as desired.

As a variant of the above method, before sintering, a special projection (eg FIG. 1) is provided as an opening into the envelope.
It should also be noted that it is not necessary to make the ears 28 of FIG. 2, the protrusion 32 of FIG. 3 or the rod 34) of FIG.
In principle, evaporation or sublimation can occur without openings into the interior of the envelope because the wax core 20 can diffuse out through the walls of the envelope before the walls become denser by sintering. The openings into the envelope can be machined after sintering if desired.

Another variation involves the use of an annulus surface on at least one of the plungers 14, 16 as shown, for example, at point 44 on the upper plunger 14 in FIG. The surface is recessed inwardly from the surrounding strip portion 46 by a shallow step at point 48.
This feature promotes densification along the circumference of the green envelope and the final envelope after sintering,
The degree of densification depends on the compression performance of the core 20 and the mixture 18.

Another variant of the invention involves the use of a plunger whose compression surface is coated with a layer of flexible material, for example polyurethane. As a result, uniform pressure is easily applied to the entire surface of the envelope.

In this regard, in use, the envelope has the purpose of holding molten sodium anode material in a high temperature electrochemical storage battery of the general type described below, wherein the opening obtained in the ear 28 or protrusion 32 is a reservoir of molten sodium and It should be noted that it has the purpose of being an inlet / outlet for locating the inner cavity of the envelope which is connected to / or another similar envelope containing molten sodium.

In FIG. 9, similar to FIG. 1, reference numeral 10 generally indicates the mold and die placement during uniaxial compression into a holder in the form of a laterally flat envelope which is compressed by the method of the present invention. Shows. This device is a mold or die body 12
And a pair of movable die plungers 14 and 16. 9 use the same reference numbers as in FIG. 1 unless otherwise noted.

Therefore, the inside of the mold 12 has a particle size of 10-100 μm mixed with 15% by mass of polyethylene glycol.
Agglomerates 18 of granular β ″ -alumina particles are shown. Within the particles 18 is embedded a core 20 (see also FIG. 10, which represents a similar core at 20) which is a polyethylene glycol casting. ..

The core 20 of FIG. 9 is a rectangular flat slab or plate having a plurality of through openings 22 that are evenly spaced from one another and that extend generally throughout. Each opening 22 interconnects with a major surface 24 of the core 20,
As shown in FIG. 9, the passage has a substantially hourglass-shaped cross section. Since the wall is convex inward, the trunk is narrowed, and the entrance on the opposite side of the passage is connected to the trunk. The entrance is dish-shaped and tapers inward, with a convexly curved side cross section. The rim 24 around the core 20 is rounded, curved in a convex shape, and has a side cross section similar to the wall of the passage 22.

According to the method of the present invention, device 10 is assembled with retracted plunger 14 and plunger 16 in place, as shown in FIG. Wax and particles 1
When the granular mixture of 8 and 8 is placed inside the mold, the core 20 is embedded in the mixture as shown. This involves placing a substantially flat layer of about half the particles 18 in the mold, placing the core 20 on that layer, and placing the rest of the particles 18 as a second layer on the core 20 in the mold, 18 is a passage 22
This is done by filling the inner space and the peripheral space between the peripheral edge 24 of the core 20 and the inner wall of the mold 12. Then, the plunger 14 is uniaxially pushed into the mold 12 in the direction of the arrow 26 toward the plunger 16 to compress and solidify the particles 18 in the periphery of the core 20 and in the passages 22 to process the particles 18 into green. Create a product. Next, the plunger 14 is retracted in the opposite direction, and the green workpiece having the core 20 is removed from the mold 12.

Next, the green processed product is heated in air at atmospheric pressure or under a suitable vacuum at a temperature of up to 550 ° C., for example 400.
Heat to 0 ° C. to remove polyethylene glycol from the core 20 and in the mixture with the solidified particles 18. The green work piece is then further heated to first evaporate water (free water or surface bound or chemically bound water) from the work piece and secondly sinter the β ″ -alumina particles 18 together to form a continuous To form a homogeneous sintered polycrystalline β ″ -alumina workpiece.

This work piece is a flat hollow envelope and one flat, continuous internal cavity in the form of a gap opened by a core 20 between the sintered plates of the sintered material formed on the main surface of the envelope. I have a torso. The particles 18 in the passages 22 are sintered and integrated into the major surface of the envelope to reinforce it and provide a support or tether at regular intervals from the major surface. The major surface of the envelope is a plate formed from layers of particles 18 on either side of the core 20 within the mold 12.

For the hourglass type of support or tether from the shape of the passage 22 having a rounded edge, which is associated with the major surface, also the rounded circumference of the envelope (resulting from the edge 24 of the core 20). With respect to the edges, it will be appreciated that the sintered work pieces tend to be more resistant to cracking as compared to sharp edges (see Figure 1). Such cracking is caused by thermal stress or stress caused by changes in pressure on the envelope wall. It should also be noted that in order to actually remove the polyethylene glycol, there need not be openings in the green processed product. In practice, after sintering, it will be a substantially airtight and airtight processed product, but polyethylene glycol can diffuse through the walls of the green processed product, which is sufficiently permeable for this purpose. The absence of such an opening is advantageous as it protects the inside of the holder, keeps it in a pure state and has a long shelf life. If desired, an opening can be mechanically opened in the internal cavity of the work piece just prior to use, for example by drilling.

If desired, the plungers 14, 16 may have an annulus surface as shown at location 44. The surface is recessed inwardly from the surrounding strip portion 46 by a shallow step at point 48. This promotes densification along the peripheral edge of the green envelope and the sintered ceramic envelope.

In FIG. 10, the core is generally designated as 20, and the same reference numbers as in FIG. 9 are used for the same parts. The main difference is that the core 20 of FIG. 10 has a surface layer 50, which is mixed with carbon balls of similar size in a suitable proportion for use in the processed product β ″ −. Contains particles of wicking material, such as particles of alumina 18. During sintering, this carbon burns out and is a permeable sintered β ″ that lines the cavities or voids of the sintered envelope.
-Alumina layer remains. This permeable lining is suitable for wicking molten sodium from the interior of the cavity to the molten sodium layer coating the interior surface of the cavity during use as described below.

In FIG. 11, the same reference numerals as in FIG. 9 are used for the same parts unless otherwise specified. The assembly 10 is essentially similar to that of FIG. 9, but with three cores of similar appearance, namely a thick central core similar to that of FIG. 9 and numbered as in FIG. 9, with a convex bend. The difference is that it has two identical thin cores with a rim 54 and a substantially hourglass-shaped through passage 56.

The illustrated cores 20, 52 are spaced at regular intervals by a layer of particles 18 and a plurality of equally spaced polyethylene glycol spacers 58. Within the mold, the lower core 52 is above the lower layer of the particle 18, and after placing the spacer 58 therein, another layer of particles extends above the core 52, the spacer 58 being the same as this thin layer. Is the thickness.
Further on top of this thin layer is a core 20, followed by another layer of particles 18 containing spacers 58, followed by an upper core 52 and a top layer of particles 18.

During solidification in the mold 12, the spacer 58 is pressed firmly against the cores 20, 52 on either side of it. When the core and spacer 58 have been evaporated, a passage is formed from the spacer, and the cavities formed by the cores 20 and 52 communicate with each other.

In use, the holder made with the assembly shown in FIGS. 9 and 11 is an anode holder containing molten sodium in a high temperature electrochemical battery which is electrochemically described below with respect to FIGS. 19 and 20. It is of the type described. In such a battery, the holder is sandwiched between two cathode parts within the battery case.
In this case, the holder made with the assembly of FIG. 9 may have an opening machined to connect to an external reservoir of molten sodium. However, in the case of FIG. 11, the created holder has the central cavity left in the core 20,
This acts as a reservoir for molten sodium. Sodium flows into the cavity formed by the core 52 to a location near the surface of the holder, enhancing the transport of sodium ions from and to the cathode portion. Of course, if desired, the entire core 52 and spacer 58
A mixture of β ″ -alumina particles and carbon balls similar to those described for the surface layer 50 of the core 20 of FIG. 10 may be included and, after sintering, within the cavity formed by the core 52 and the spacer 58. The inside of the created space is filled with a permeable sintered β ″ -alumina having a suction capacity by capillary action.

In FIG. 12, a core 20 similar to the core 20 of FIG. 9 is shown. However, the core of FIG. 12 is a hollow cylinder, and the core 20 of FIG. 12 is an hourglass-shaped passage 22 and rounded edges 2 at the end similar to those described for the core 20 of FIG.
Have five.

The core 20 of FIG. 12 is used as shown in FIG. 13 to make a hollow tubular workpiece. In FIG.
A steel mandrel 60 is shown concentric with the tubular latex sheath 62 and radially spaced from the sheath. The sheath 62 is closed by a steel end lid 64. The mandrel 60 is its pedestal or pedestal 66.
On the pedestal and is shown embedded on the pedestal in a mass of particles 18 that fills the sheath 62. On the mandrel 60 is a cylindrical steel or rubber plug 6
There is 8. The core 20 of FIG. 12 is radially separated between the mandrel 60 and the sheath 62 and embedded within the particle 18. The upper end of the mandrel is dome-shaped and the lower end of the plug 68 is correspondingly recessed,
Between the upper end of the mandrel and the lower end of the plug is a curved rounded layer 70 of particles 18. The outer diameter of the pedestal 66 is the sheath 6
2 in the core 20 and the outer diameter of the plug 68 in the core 20. The pedestal 66 is on the lower cap 64, and the upper cap 64 is on the plug 68. Mandrel 60, sheath 62, cap 64
The plug and plug 68 are assembled into a device generally designated 72 in FIG. 13, the purpose of which is shown in FIGS.
This is the same as the purpose of the device 10 of FIG.

To assemble the device 72, the lower cap 64 is placed on the lower end of the sheath 62 and the mandrel 68 is placed on the lower cap 64 and within the sheath 62. As shown, a small amount of particles 18 are introduced into the sheath 62 from above until the pedestal 64 is sufficiently covered. Next, the core 20 is inserted from above into the sheath 62 and placed on the particles placed concentrically between the mandrel 60 and the sheath 62. Next, the particles 18 are further put from above, below the upper end of the core 20 extending above the mandrel 60, and close to the upper end. The amount of particles is sufficient to cover the mandrel and form layer 70. Next, the plug 68 is inserted into the core 20 from above and firmly pressed while vibrating as necessary to form a rounded layer 70 having no cavity therein. Particles 18 are filled inside the remaining sheath 62, around the core 20 and the plug 68, and the upper cap 64 is put in place.

After assembly of the device 72, the method is essentially the same as described above with respect to FIGS. 9 and 11, except that the pressurization to solidify the particles 18 is applied to the sheath 6.
2 isotropic compression to the outside. Of course, mandrel 60 and plug 68 are removed from the green work piece before core 20 is removed and sintered. After sintering,
A processed product having the shape of the space filled with the particles 18 as shown in FIG. 13 is produced. The work piece has a continuous cylindrical gap or cavity (similar to the cavities and struts in the envelope created by the apparatus 10 of FIG. 9) connected to the wall by radially extending struts or tethers. It is a hollow cylinder having. The particle layer of 70 includes a mandrel 60 and a plug 68.
A partition wall is provided in the hollow cylindrical central space of the workpiece that remains after the removal of. The work piece wall at the top of the partition wall is somewhat thinner than at the bottom of the partition wall. Removal of the core at location 74 includes the cavity formed by the core 20 and the portion of the hollow cylindrical central space of the workpiece formed by the plug 68 which, in use, acts as a molten sodium reservoir for the electrochemical cell. There is a connection and sodium flows. The work piece is used in batteries of the type described below with respect to FIG. 20, but unlike FIG. 20, the sodium reservoir can be part of the work piece emptied by the plug 68 and is inside the battery case.

In FIG. 14, a more complex single core is
Is shown. The core includes pillars 78, and a plurality of disk-shaped fins 80 extending in the circumferential direction and protruding outward in the radius are arranged on the pillars at regular intervals along the length direction. The pillar 78 extends upward from the bottom fin 80,
It projects above the uppermost fin 80. The fin has passageways 22 and rounded edges 25 of the type described with respect to FIGS. 9 and 11.

In FIG. 15, the core 76 of FIG. 14 is shown embedded within the particles 18 in the corresponding latex bag 82, compressing the green article around the core 76,
A device 84 for solidifying is formed. The bag has an open top or neck at a location 86 around the top of post 78, which neck 86 is closed by a cap 64. To form the device 84, the core 76 is attached to the bag 8
The bag 82 can be inserted because it is sufficiently elastic and expandable. The core 76 is on a concentric circle of the bag 82 apart from the bottom of the bag 82.
The outer bag 82 is filled with particles 18 and is closed with a cap 78 prior to isotropic compression. After compression, the bag 82 (which is a bisected longitudinally extending split bag) is removed from the formed green article, and then the core is removed as described above and then sintered. As a result, the holder of the ceramic workpiece in the form of a hollow column (see 88 in FIG. 15) having a plurality of hollow flat envelopes (see 90 in FIG. 15) remains, and the envelope is spaced at regular intervals in the length direction of the column. Yes, the holder is a core 76
It has cavities formed by fins 80, which are connected to the inside of columns 88 formed by the cavities left after the removal of columns 78 of. Inside the hollow interior of the envelope 90 created by removing the fins 80 is an hourglass-shaped stiffening support or tether formed by the particles 18 in the passageway 22.

In FIG. 16, another form of core 76 of FIG. 6 is shown, but with a more complex structure. Here, the fins 80 are made of annular discs 92 and the posts 78 are made of annular spacers 94. In FIG. 16, the same numbers and parts are shown as in FIG. 14, and the core of FIG. 16 is used in essentially the same manner as described above for core 76 of FIG. 14 with reference to FIG. However, in order to assemble the core 76 of FIG. 16, the disks 96 and spacers 94 are stacked alternately by sliding on steel rods or bars 96. The steel rods or bars remain in place during compression with the bag 82 (FIG. 15) and the bars 96 can be easily removed after removal of the core 76 and prior to sintering. The core 76 of FIG. 16 is used to make a work piece that is essentially the same as the work piece made using the core 76 of FIG. 14 above.

FIGS. 17 and 18 show a hollow cylindrical workpiece generally designated 98. This processed product was prepared using the same device as that shown in FIG. However, in order to create the processed product 98, the upper cap 6
4 (FIG. 13) and use a mandrel (see 60 in FIG. 13) that has a flat end away from the pedestal 66.
The core 20 extends from near the pedestal 66 shown in FIG. 13 to an equally spaced position from the upper cap 64. FIG. 17
A cylindrical wall 1 having a cylindrical cavity 102 therein and connected by a radially extending support or tether 104.
A core 20 with 00 is shown. The core used is that of FIG. 12 and the supports or tethers are tubes 22 (FIG.
2) is formed inside. The cavity 102 is a permeable lining 10 made using a core 20 as shown in FIG.
6, which has a surface layer (see 50 in FIG. 10) containing particles of wicking material as described with reference to FIG.

In FIG. 19, a high temperature rechargeable electrochemical storage battery is generally designated 108. The battery 108 has a cylindrical case 110, which is an electrochemically conductive body, in which a holder 98 made by the method of the present invention is concentrically arranged. The holder 98 is essentially the same as that of FIGS. However, the difference is that it has a dome-shaped upper end 112 made with the device shown in FIG. 13, and there is no upper cap 64, and the sheath 62 (FIG. 13) is inside the dome-shaped end of the mandrel 60. Converging (or similar), forming a curved space on the mandrel for the particles 18 forming the dome-shaped end 112 of the holder 98, the sheath 62 forming the neck 114 of the holder 98. It also has an upper neck. A core was used similar to that used in FIG. 17, except that the core was the cavity 10 of FIG.
It was cast to have a dome upper end and a neck portion corresponding to the shape of 2.

The neck 114 of the holder 98 is connected to the case 110 by an insulating seal 116, and the location 118
It is enclosed by a closed enclosure. The cavity 102 is filled with molten sodium 102. A cathode end post 122 connected to the case 110 and an anode end post 12 connected to the sodium 120 via an enclosure 118.
There is 4. The holder 98 is dipped or buried in the cathode material 126, which may be sulfur / sodium sulfide / polysulfide. The cathodic material may be that of a cathodic material comprising an active cathodic material of a halide of a transition metal dispersed in a matrix of electrically conductive material, the electrically conductive material being porous, permeable and alkali metal. It is impregnated with a haloaluminate molten salt electrolyte. Thus the workpiece electrolyte material is NASICON, β-alumina or preferably β ″ -alumina, the molten electrolyte is eg NaAlCl ₄ in contact with some NaCl in the matrix, and the active cathode material is suitable. Transition metal halides such as FeCl ₂ or NiC
It is l ₂ .

In FIG. 20, another battery is represented by 108, and the same numbers as in FIG. 19 indicate the same parts. In FIG. 20,
There is no wicking porous lining 106 and enclosure 118. Instead, a sodium 120 containing reservoir 128 below the inert gas space 130 connects to the neck 114.

Although not shown, the holder 98 is shown in FIG.
It can be created with the type shown in FIG. The holder has three cavities 10 similar to the three cavities in the flat envelope holder manufactured by the apparatus 10 of FIG.
2, a thick central cylindrical cavity and two cavities on the opposite side of the cavity, spaced from it and connected by a space formed by a spacer having the same function as the spacer 58 of FIG. It should be noted that there is a thin cavity. These spacers and thin cavities can be filled with porous wicking material (see 106 in FIGS. 17 and 18).

Finally, the holder manufactured by the apparatus 72 of FIG. 13 is the holder 9 of the battery 108 of FIG. 19 and FIG.
It should be noted that it could be used in a battery, essentially as using 8. In this case the holder has a portion of a hollow cylindrical central space made of a plug 68 (FIG. 13) which acts as a sodium reservoir (see 110 in FIG. 12). This reservoir is the reservoir 128 of FIG.
Unlike the one in the battery case,
16) is preferably connected to the case by an enclosure (see FIG. 1).
9 124)).

[0072]

Experimental Example In a typical embodiment of the present invention, the core 20 (see FIGS. 2 and 3) is formed by molding polyethylene glycol (for example by casting or uniaxial compression) into any of the shapes shown in FIGS. To do. From different ones, average particle size 50-10
A mixture of 0 μm β ″ -alumina powder and polyethylene glycol is made. 15% by weight of β ″ -alumina in dry matter, β ″ -alumina and 30% by weight of polyethylene glycol in aqueous solution. After mixing, spray drying is performed with a dryer having an outlet temperature of 130 ° C., and the water content is 10% by mass or less.

After mounting on the die, the pressure of 30 MPa is applied to reduce the thickness of the envelope from 5 mm to 2 mm. The thickness of the core is 1 mm, so the total thickness of the compressed green work piece is 5 mm.

The green processed product is then heated by the following heating method under atmospheric pressure to remove polyethylene glycol,
The water is removed by evaporation, the water is also separated from the β ″ -alumina, and then the work piece is sintered.

Room temperature -400 ° C, 25 ° C / hr (in air) 400-1600 ° C, 100 ° C / hr (in air) 1600-1617 ° C, 60 ° C / hr (in air) 1617-1000 ° C, 240 ° C / hr (under air) 1000 ° C.-room temperature, 360 ° C./hr (under air) As described with reference to the drawings and examples, a simple and inexpensive method for producing the desired type of envelope, suitable for mass production. What is provided is a feature of the present invention.

Of course, while the method of the present invention has been described with reference to a ceramic holder or envelope of solid electrolyte material for use in an electrochemical cell, in principle a similar holder or envelope for other purposes is produced from other ceramic materials. The method according to the invention can also be used for this.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a green holder made by the method of the present invention during uniaxial compression with a die in a mold into a green processed product.

2 is a schematic three-dimensional view of a core for use with the mold of FIG.

3 is a view similar to FIG. 2 of another core for use with the mold of FIG.

4 is a view similar to FIG. 1 of another holder of the present invention during uniaxial compression with a die in a mold into a green workpiece.

FIG. 5 is a schematic perspective view of a core used for isotropic compression of the holder of the present invention.

FIG. 6 is a schematic perspective view of a core used for isotropic compression of the holder of the present invention.

FIG. 7 is a schematic perspective view of a core used for isotropic compression of the holder of the present invention.

FIG. 8 is a schematic perspective view of a core used for isotropic compression of the holder of the present invention.

FIG. 9 is a schematic side sectional view of another green holder made by the method of the present invention while being uniaxially compressed by a die into a green processed product in a mold.

FIG. 10 is a schematic side sectional view of a wax core used in the mold of FIG.

FIG. 11 is a view similar to FIG. 9 of another green holder made by the method of the present invention during uniaxial compression into a green processed product.

FIG. 12 is a perspective view of a hollow cylindrical core used in the method of the present invention.

FIG. 13 is a schematic vertical sectional view of another holder of the present invention during uniaxial compression into a green processed product.

FIG. 14 is a perspective view of another core used in the method of the present invention.

15 is a vertical cross-sectional view of another holder of the present invention during isotropic compression around the core of FIG. 14 to produce a green product.

16 is a vertical cross-sectional view of a modification of the core of FIG.

FIG. 17 is a vertical sectional view of a hollow cylindrical holder of the present invention.

18 is a cross-sectional view taken along the line XVIII-XVIII in FIG.

FIG. 19 is a schematic vertical sectional view of a high temperature electrochemical cell using the holder of the present invention.

20 is a view similar to FIG. 19 of another similar battery using the holder of the present invention.

[Explanation of symbols]

 10 type 12 type main body 14 movable plunger 16 movable plunger 18 particles 20 core 22 passage 28 knob 30 green processed product 32 protrusion 34 rod 36 opening 38 opening 40 wing portion 60 mandrel 62 sheath 64 cap 66 pedestal 68 plug 70 layer 72 device 76 core 78 Pillars 80 Fins 82 Bags 88 Pillars 90 Envelopes 92 Discs 94 Spacers 96 Bars 98 Holders 100 Cylindrical Walls 102 Cavities 104 Supports 106 Linings 108 Batteries 110 Cases 112 Dome Shaped Top Ends

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // C04B 35/10 A 8924-4G

Claims (11)

[Claims] 1. A method of manufacturing a holder made of solid ceramic material, comprising placing at least one core in a mass of granular ceramic material or its granular precursor material, compressing and solidifying the granular material around each core. Then, the core is at least partially embedded in the granular material, and each core is removed from the solidified mass of the granular material so that the green processed product with cavities remains inside, and the green processed product is Sintering to create a sintered single piece of ceramic material having at least one cavity for the final contents of the holder, each core being formed, and a particulate material being formed. Are arranged such that at least a portion of each core is in the form of a thin slab or layer sandwiched between a pair of layers of granular material, and after sintering at least a portion of each cavity is a sintered ceramic material. of Each slab or layer has at least one through-opening through which the granular material is filled, the granular material in each opening having a thin gap between the interdigitated plates. The compression causes the granular material in the gap to solidify,
A method in which after being sintered, it forms a bridge across the gap between the connected plates and is sintered to the bridge so that the bridge can act as a support or bridge between the connecting plates, strengthening the holder. 2. Each slab or layer used has a plurality of through openings therethrough, the openings being spaced apart from one another and after sintering the plates are connected to each other by a matrix of said bridges spaced apart from each other. The method of claim 1. 3. The method of claim 2, wherein each opening is formed such that the bridges are in the form of short cylinders or columns that are evenly spaced from each other and distributed throughout the gap. 4. Each core consists of at least one single slab, each opening being shaped such that its side cross-section is in the shape of a passageway with a radially inwardly convexly curved wall. Each passage has a pair of inlets at opposite ends, each inlet is dish-shaped and thus tapered toward the inside of the passage in the axial direction, and each slab is convexly curved and rounded around. 4. A method according to any one of claims 1 to 3 having edges. 5. The ceramic material is a solid electrolyte material for holding the active electrode material of a high temperature electrochemical cell, wherein each core is completely surrounded by the granular material, and thus, after compression, is completely solidified granular material. 5. The method according to claim 1, further comprising: forming a workpiece having a closed cavity therein by sintering, and forming a supply opening from the outside of the holder into the cavity after sintering. The method described in crab. 6. The compression is carried out at a temperature of -10 ° C. to + 500 ° C. and a pressure of 30-310 MPa, and 0.5-30% by weight of organic binder is mixed with the granular material before placing each core in the granular material. A method as claimed in any one of the preceding claims, wherein the method comprises the steps of sintering, which serves to remove the binder out. 7. A pair of opposing cores in the form of slabs which are spaced apart facing one another by a layer of granular material, each core having a different thickness. the method of. 8. There are three opposed cores in the form of slabs which are face-to-face separated by a layer of granular material, the central core being separated from the outer core between the other two outer cores. 7. The method of any of claims 1-6, wherein the central core is thicker and the central core is thicker than the outer core. 9. When the cores are in the granular ceramic material, the thicker cores are each separated from the other cores by spacers of at least one core material, each spacer being a workpiece duct after sintering, and thus 9. A method according to claim 7 or 8, wherein the cavities made of thick core are connected to other cavities respectively. 10. At least one of said cores has particles of wicking material or precursor material thereof, at least on its surface or in a portion embedded in the core material, so that the sintering is inside a cavity made of the core. 10. A method according to any one of the preceding claims, wherein the surface is provided with a porous wicking material that wicks the final contents of the holder in liquid form. 11. A holder made of a solid electrolyte material produced by the method according to any one of claims 1 to 10.