Rayovac Corporation

Robert J Jacus

James A Senn

Kenneth R Kusel

Janna L Rose

Douglas Pagoria

A separator system for an alkaline cell comprises an absorbent layer and a barrier layer adjacent to the absorbent layer. The arrangement of the separator material in the cell improves separation between anode and cathode, increases the volume available in the cell for active material or void volume, thereby improving cell performance or enhancing reliability of cells containing the system.

Alkaline cell and separator therefor

This invention pertains to rechargeable zinc alkaline electrochemical cells. In cells of the invention, the anode current collector comprises copper, and from about 0.5% by weight to about 11% silicon. Preferred compositions for the anode current collector comprise from about 1% by weight silicon to about 6% by weight silicon. Cells embodying anode current collectors of the invention exhibit reduced current flow under anode polarization in alkaline conditions, and reduced cell expansion under abusive electrical drain conditions. The cells are less susceptible to oxidation of the anode current collector, which is typically irreversible, than known brass anode current collectors. In general, cells of the invention are less susceptible to, and generally do not exhibit as much, irreversible chemical reaction activity, as conventional current collectors, especially oxidation of copper at the anode current collector.

Rechargeable alkaline electrochemical cell

During repeated cycling of alkaline manganese dioxide cells, it is critical to ensure that adequate barrier protection is formed and maintained between the anode and cathode of the cell to prevent shorts from occurring between the cathode and anode. However, the potential also exists for anodic zinc to migrate via the absorbent separator and create a short path to the cathode. To prevent this, cells are fabricated wherein a separator is placed into the cells, a hot melt material is metered into the cell so that the hot melted material flows under the bottom edge of the separator, which is then pushed down and seated in the hot melt material as it cools. The end result is a barrier which is forms at the bottom of the cell and at both sides of the separator and virtually eliminates shorts from developing between the electrodes.

Rechargeable alkaline round cell having hot melt barrier

During repeated cycling of alkaline manganese dioxide cells, it is critical to ensure that adequate barrier protection is formed and maintained between the anode and cathode of the cell to prevent shorts from occurring between the cathode and the anode. However, the potential also exists for anodic zinc to migrate via the absorbent separator and create a short path to the cathode. To prevent this, cells can be fabricated whereby a separator barrier is placed into the cells, a hot melt sealant is metered into the cell so that the sealant flows under the separator barrier, the separator barrier is pushed down and seated into the hot melt. The end result is a separator barrier which is sealed at the bottom of the cell and at both sides of the separator barrier and virtually eliminates shorts from developing between the electrodes.

Alkaline manganese dioxide cells

In accordance with the present invention, an electrochemical cell is disclosed comprising a metal oxide cathode; an anode/electrolyte mixture which contains a zinc anode material and an aluminum compound additive as an source of aluminum ions (e.g., an aluminum salt). The anode/electrolyte mixture may also contain a source of sulfate ions (e.g., a metal sulfate). The anode/electrolyte mixture can also include a suitable carrier (e.g., gelling agent, buffer) for admixing the various components of the mixture.

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Madison, WI, United States of America

Robert J Jacus