Duracell Inc.

Paul Cheeseman

Viet H Vu

William T McHugh

Bhupendra Kanchanial Patel

Lucien Paul Fontaine

Jane A Blasi

Jeffrey S Hewes

Robert J Pinault

Reynald Cantave

Alex Kaplan

Michael McDermott

Jeffrey Poirier

Yelena Kouznetsova

A current interrupt mechanism for electrochemical cells is disclosed. A thermally activated current interrupt mechanism is integrated into an end cap assembly for an electrochemical cell. The thermally responsive mechanism preferably includes a free floating bimetallic disk or shape memory alloy member which deforms when exposed to elevated temperature causing a break in an electrical pathway within the end cap assembly. This prevents current from flowing through the cell and effectively shuts down an operating cell. The thermally responsive mechanism may include a heat producing electrical resistance means, preferably a Zener diode, to enhance thermal sensitivity. The end cap assembly may include a pressure responsive mechanism which ruptures when there is extreme gas pressure buildup. Gas is allowed to escape from the cell interior to the external environment through a series of vent apertures within the end cap assembly.

Current interrupter for electrochemical cells

A current interrupt assembly for electrochemical cells is disclosed. The current interrupter assembly may be a self-contained, sealed unit which may be separately inserted into the cell during cell construction. Several current interrupt assemblies may be inserted in the cell. The current interrupter assembly has particular utility for thin rechargeable cells and when inserted in the cell forms a portion of the electrical pathway between a cell electrode and corresponding terminal. The current interrupt mechanism comprises a thin thermally responsive member preferably comprising a disk of a shape memory metal alloy having a curved surface. The current interrupt mechanism may include a heat producing electrical resistance means, preferably a Zener diode in proximity to the thermally responsive member. When cell temperature exceeds a predetermined value the disk deflects to cause a break in the electrical pathway within the assembly. The assembly may include therein a flexible electrically conductive member which forms a part of the electrical pathway within the assembly and which is physically responsive to deflection of the thermally responsive member. The assembly may also include a pressure actuated diaphragm which may form a portion of the assembly housing. When the cell internal pressure exceeds a predetermined level the diaphragm deflects causing a break in the electrical pathway within the assembly, thereby shutting down the cell.

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Holliston, MA, United States of America

Paul Cheeseman