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AssigneeDuracell Inc.
InventorsViet H. Vu, Jane A. Blasi, Robert J. Pinault, William T. McHugh, Lucien P. Fontaine
Estimating the term…
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 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. Alternatively, the thermally responsive mechanism may include a meltable mass of material which melts when exposed to elevated temperature to break an electrical pathway within the end cap assembly. The end cap assembly may also include integrated therein a pressure responsive current interrupt mechanism. If the internal gas pressure within an operating cell exceeds a predetermined value, the pressure responsive mechanism activates to sever an electrical pathway within the end cap assembly to prevent current from passing through the cell. The pressure responsive mechanism may include a diaphragm 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.
An end cap assembly for application to an electrochemical cell having a positive and a negative terminal and a pair of internal electrodes, said end cap assembly comprising a housing and an exposed end cap plate, said plate functional as a cell terminal, said end cap assembly having an electrically conductive pathway therethrough permitting the end cap plate to be electrically connected to a cell electrode when said end cap assembly is applied to a cell, said end cap assembly further comprising a) thermally responsive means for preventing current from flowing through said electrical pathway, wherein said thermally responsive means is activatable when the temperature within said end cap assembly reaches a predetermined level causing a break in said electrical pathway, and b) a pressure responsive means comprising a rupturable member located at the end of said end cap assembly opposite said end cap plate, said rupturable member rupturing when gas pressure on the side thereof furthest from said end cap plate reaches a predetermined level producing a rupture in said member allowing gas to pass therethrough.
In an electrochemical cell of the type formed by an end cap assembly inserted into an open ended cylindrical case for the cell, said cell further having a positive and a negative terminal and a pair of internal electrodes, wherein said end cap assembly has a housing and an exposed end cap plate, said end cap plate functional as a cell terminal, the improvement comprising said end cap plate being electrically connected to one of said electrodes through an electrically conductive pathway within said end cap assembly, wherein said end cap assembly comprises a) thermally responsive means for preventing current from flowing through the cell, wherein said thermally responsive means is activatable when the temperature within the cell reaches a predetermined level causing a break in said electrical pathway between said end cap plate and said electrode thereby preventing current from flowing through the cell and b) pressure responsive means allowing gas from the interior of the cell to pass into the interior of said end cap assembly when internal gas pressure within the cell reaches a predetermined level.
An end cap assembly for application to an electrochemical cell having a positive and a negative terminal and a pair of internal electrodes, said end cap assembly comprising a housing and an exposed end cap plate, said plate functional as a cell terminal, said end cap assembly having an electrically conductive pathway therethrough permitting the end cap plate to be electrically connected to a cell electrode when said end cap assembly is applied to a cell, said end cap assembly further comprising a) thermally responsive means for preventing current from flowing through said electrical pathway, wherein said thermally responsive means is activatable when the temperature within said end cap assembly reaches a predetermined level causing a break in said electrical pathway, wherein said thermally responsive means comprises a chamber within said end cap assembly and further comprises a bimetallic member and a resilient electrically conductive member, the resilient member forming a portion of said electrical pathway and wherein said bimetallic member rests freely on a surface of an electrically insulating member within said end cap assembly, wherein when the cell temperature within said assembly reaches a predetermined level the bimetallic member deforms thereby pushing against said resilient metallic member causing a break in said electrical pathway.
An end cap assembly for application to an electrochemical cell having a positive and a negative terminal and a pair of internal electrodes, said end cap assembly comprising a housing and an exposed end cap plate, said plate functional as a cell terminal, said end cap assembly having an electrically conductive pathway therethrough permitting the end cap plate to be electrically connected to a cell electrode when said end cap assembly is applied to a cell, said end cap assembly further comprising a) thermally responsive means for preventing current from flowing through said electrical pathway, wherein said thermally responsive means is activatable when the temperature within said end cap assembly reaches a predetermined level causing a break in said electrical pathway, wherein said thermally responsive means comprises a chamber within said end cap assembly and further comprises a bimetallic member and a resilient electrically conductive member, the resilient member forming a portion of said electrical pathway and wherein said bimetallic member rests freely on a surface of an electrically insulating member within said end cap assembly, wherein a portion of said resilient metallic member is sandwiched between a portion of said end cap plate and a portion of said electrically insulating member and wherein the end cap assembly comprises a contact plate which forms part of said electrical pathway, wherein said resilient member is in electrical contact with said contact plate, wherein when the cell temperature within said assembly reaches a predetermined level the bimetallic member deforms thereby pushing against said resilient metallic member causing a break in said electrical pathway.
An end cap assembly for application to an electrochemical cell having a positive and a negative terminal and a pair of internal electrodes, said end cap assembly comprising a housing and an exposed end cap plate, said plate functional as a cell terminal, said end cap assembly having an electrically conductive pathway therethrough permitting the end cap plate to be electrically connected to a cell electrode when said end cap assembly is applied to a cell, said end cap assembly further comprising a) thermally responsive means for preventing current from flowing through said electrical pathway, wherein the thermally responsive means comprises a resilient conductive member in electrical contact with said end cap plate, and a meltable mass of material holding said resilient conductive member in electrical connection between said end cap plate and another conductive portion of the end cap assembly, said other conductive portion adapted to be electrically connected to a cell electrode when the end cap assembly is applied to a cell thereby providing an electrical connection between said end cap plate and said electrode during cell operation, wherein said thermally responsive means is activatable when the temperature within said end cap assembly reaches a predetermined level causing a break in said electrical pathway, wherein when the cell temperature reaches a predetermined level said mass of material melts thereby causing movement in said resilient metallic member to sever the electrical connection between said end cap plate and said cell electrode thereby preventing operation of the cell.
Dependencies are inferred from the claim text.