Lilliwyte Societe Anonyme

Programme 3 Patent Holdings

Chloride Silent Power, Ltd.

James H Duncan

Roger J Bones

Johan Coetzer

David A Teagle

Peter Barrow

Ivor E Denton

Marion R Rance

Arnold Van Zyl

Rodney J Stead

Angus I Kingon

Jacobus H De Jager

A laterally compressed envelope of solid electrolyte material is provided for use as an electrode holder in an electrochemical cell. It has two opposed major faces sealed together along at least part of the periphery of the envelope, each major face being provided by a sheet of said solid electrolyte material. Each sheet is provided on its inner surface with a plurality of ribs or corrugations extending alongside one another, each rib or corrugation of each said sheet crossing over a plurality of the ribs or corrugations of the other said sheet. The envelope has an internal volume, between the sheets, defined at least in part by grooves or valleys between the ribs or crests of the corrugations. Each part of said internal volume is in communication with each other part of said internal volume. The invention also provides a method of making the envelope, and an electrochemical cell in which the envelope forms an electrode holder.

Electrochemical cells

The invention provides a high temperature rechargeable electrochemical power storage cell comprising a cell housing defining a cathode compartment containing a cathode and containing an anode structure located within the cathode compartment and comprising a plurality of holders filled with active anode material which is molten at the operating temperature of the cell. The anode structure defines a conduit containing active anode material and the holders are flattened in shape and spaced along the conduit in series from one another. The interior of each holder is in communication with the conduit and each holder has a pair of oppositely outwardly facing major faces extending transversely to the conduit and comprising a material which is a conductor of the active anode material. The cathode occupies the spaces between the holders and the cell includes a reservoir for active anode material in communication with the conduit, the reservoir in all states of charge of the cell being at least partially filled with active anode material.

Electrochemical cell

The invention provides a compressed envelope of solid electrolyte for holding an electrode in an electrochemical cell. The envelope comprises corrugated sheets joined along their edges. The sheets are aligned with each other so that their corrugations extend parallel along the length of the envelope and a space is defined between the sheets. The corrugations of the sheets nest in each other where the sheets are joined together at the ends of the envelope. The invention also provides a method of making the envelope and a cell having an electrode held in said envelope.

Electrode holder

The invention provides a method of making a flattened solid electrolyte, e.g. .beta.-alumina, envelope for use as an electrode holder in an electrochemical cell. A mouldable mixture of the .beta.-alumina with a binder is formed into sheet material and two panels of the sheet material are joined together along their peripheral edges to form the envelope. Spacing and reinforcing means is provided between the panels to space them apart and to reinforce the envelope. The edges of the panels are joined together using pressure, heat and/or solvent, after which are envelope is heated to cure the binder, volatilize the cured binder and sinter the solid electrolyte.

The invention provides a method of making a composite beta-alumina artifact, such as a separator tube for an electrochemical cell, comprising two beta-alumina portions which are sealed together in a sealing zone, namely an inner portion and an outer portion which extends peripherally around the inner portion and embraces it in the sealing zone. The method comprises pressing the inner and outer portions from powders which, when sintered, shrink and form integral beta-alumina artifacts. The portions are then arranged so that the outer portion extends around the inner portion and embraces it in a sealing zone. The portions are then sintered to cause them to seal together hermetically in the sealing zone while converting each of the portions into a beta-alumina artifact. The portions are made so that the outer portion undergoes a greater degree of shrinkage during sintering than the inner portion and the portions are pressed so that the spacing between the portions where the outer portion extends around and embraces the inner portion is such that, upon sintering, the outer portion shrinks on to the inner portion to provide a hermetic peripheral seal between the portions.

Manufacture of beta-alumina artifacts

A method of making beta'-alumina comprises dispersing in a precursor of aluminum oxide a member of the group comprising sodium oxide and its precursors, and dispersing in the precursor of aluminum oxide a spinel stabilizer which is a member of the group comprising spinel-forming oxides and the precursors thereof, to form a mixture. The mixture is then heated to a temperature at which at least some of the precursor of aluminum oxide is converted to beta'-alumina. The precursor of aluminum oxide is one which, when calcined in air by itself, has a calcination product which, when subjected to X-ray diffraction, displays a predetermined X-ray diffraction trace. The X-ray diffraction trace is one whose peak with the highest intensity in the 2 (theta) range of 44.degree.-48.degree. and whose peak with the highest intensity in the 2 (theta) range of 63.degree.-69.degree. respectively have maximum intensities and integrated intensities which comply with equations (I) and (II):

Method of making beta'-alumina

In the manufacture of beta-alumina, particularly for use as a solid electrolyte in an electro-chemical cell or other energy conversion device, a compact of beta-alumina particles or of particles which react together on heating to form beta-alumina is sintered in a succession of cycles of heating and cooling such that not less than 5% and not more than 95% of the overall linear shrinkage takes place in any one cycle.

Growing community of inventors

Stafford, United Kingdom

James H Duncan