End cap seal assembly for an electrochemical cell

Abstract

An end cap seal assembly for an electrochemical cell such as an alkaline cell is disclosed. The end cap assembly comprises a convoluted end cap which may also function as a cell terminal and an underlying insulating sealing disk. The insulating sealing disk comprises a central boss and radially extending arm terminating in a downwardly sloped elbow and upwardly sloped peripheral edge. The end cap disk has at least one vent aperture therethrough which faces the ambient environment. The insulating disk has an annular groove in its top or bottom surface, which preferably circumvents the central boss. The base of the groove defines an a rupturable membrane portion of the insulating sealing disk. The rupturable membrane is designed to rupture, preferably when the cell internal gas pressure reaches a level between about 150 and 900 psig (1034 x 10<3> and 6206 x 10<3> pascal gage) advantageously, between about 150 and 700 psig (1034 x 10<3> and 4827 x 10<3> pascal gage). The seal may be made of nylon, polyamide, polypropylene, sulfonated polyethylene.

Description

technical field [0001] The present application relates to an end cap assembly for sealing electrochemical cells, especially alkaline cells. The present application relates to a rupturable device in an end cap assembly that allows gas to escape from the cell interior to the environment. Background technique [0002] Conventional electrochemical cells, such as alkaline cells, consist of a cylindrical casing with an open end and an end cap assembly inserted into the casing to seal it. Conventional alkaline batteries typically include an anode comprising zinc, a cathode comprising manganese dioxide, and an alkaline electrolyte comprising aqueous potassium hydroxide. After the contents of the cell are prepared, the cell is closed by bending the casing edge over the end cap to seal the cell tightly. The end cap assembly includes an exposed end cap plate serving as a battery terminal and typically includes a plastic insulating insert which seals the open end of the housing. A pr...

AI Technical Summary

Problems solved by technology

A problem with the design of all types of electrochemical cells, especially alkaline cells, is that they may generate gas if the cell is continuously discharged beyond a certain point, usually close to the point at which the cell's usable capacity is completely depleted

The end cap assemblies disclosed in these references generally have a high profile, that is, occupy a large percentage of the cell's internal volume, or they cannot reliably withstand even hundreds of pounds per square inch gauge (psig) pressure in the cell. ) gas pressure increases, or there are weak points in the seal, which will be chemically attacked and corroded by the alkaline electrolyte

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