Duracell Inc.

Terrence F Reise

Alwyn H Taylor

Peter R Moses

Bhupendra Kanchanial Patel

John D Sillesky

James H Him

Fred J Berkowitz

Paul L Bedder

James B McVeigh, Jr

Andre Walker

The present invention relates to an improved process for producing beta manganese dioxide and for producing cathodes from said manganese dioxide. The process comprises heating gamma manganese dioxide at at least 450.degree. C. for up to one hour in order to convert a majority of the gamma manganese dioxide to the beta phase without forming detrimental amounts of lower oxides.

Process for producing beta manganese dioxide

This invention pertains to an improved means of making electrical and mechanical contact to metal foil electrode in an electrochemical cell. A conductive element is used which has a multiplicity of teeth projecting therefrom. The teeth pierce through the metal foil electrode and are bent over to be flush with the electrode surface. A strong mechanical and electrical bond results.

Electrochemical cell asssembly

The invention relates to spirally wound electrochemical cells in which the anode tab is located on a section of the anode that is sandwiched on both sides by cathode. This eliminates or minimizes problems normally associated with voltage reversal.

Spirally wound electrochemical cells

This invention provides a design for spirally wound electrochemical cells which improves their safety during abuse such as voltage reversal. The invention comprises coupling a first segment of inert conductive metal to the cathode and a dendrite target comprised of an inert conductive metal to the anode. When these electrodes are spirally wound together the two segments of inert conductive metal face each other, held in physical separation by the separator, whereby during voltage reversal a dendrite grows from said first segment to said dendrite target.

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Sudbury, MA, United States of America

Terrence F Reise