Battery separator
AssigneeW. R. Grace & Co.
InventorWai M. Choi
Life of this patent
Estimating the term…
Abstract
The present invention is a sheet material for use in alkaline batteries as a separator or interseparator. The sheet is formed of about 30 to about 70 percent polyolefin synthetic pulp, from about 15 to about 65 percent alkali resistant inorganic filler and from about 1 to about 35 percent of one or more long fibers, wherein at least some, if not all of the fiber is a water swellable polyvinyl alcohol based fiber and any remaining long fiber is a nonwater swellable fiber. The water swellable fiber during processing of the sheet forms a gel-like network when contacted by water which retains the filler and bonds the remaining materials together. The resulting sheet has increased tensile strength and alkali resistance and is especially useful in automated battery manufacturing processes.
Claims20
A sheet material for use in an alkaline battery system comprising from about 30 to about 70 weight percent of the sheet material of polyolefin synthetic pulp, from about 15 to about 65 weight percent of the sheet material of an alkali resistant inorganic filler, and from about 1 to 35 weight percent of the sheet material of long synthetic fibers having lengths of at least about 0.25 inch wherein at least some of the long synthetic fibers are water swellable vinyl alcohol so as to bind at least some of the remaining ingredients together.
An alkali resistant sheet material comprising from about 30 to about 70 weight percent polyolefin synthetic pulp, from about 15 to 65 weight percent of filler and from about 1 to 35 weight percent of one or more long synthetic fibers, wherein at least some or all of the long synthetic fibers are water swellable vinyl alcohol.
A battery separator for use in alkaline batteries comprising a sheet of from about 30 to about 70 weight percent of the sheet of polyolefin synthetic pulp, from about 15 to 65 weight percent of the sheet of an alkali resistant inorganic filler, from about 0.5 to 17.5 weight percent of the sheet of a water swellable vinyl alcohol long fiber and from about 0.5 to about 17.5 weight percent of the sheet of a nonwater swellable long fiber.
An alkaline battery comprising one or more positive electrodes, one or more negative electrodes, an alkaline based electrolyte solution and a sheet material for use as a separator or interseparator comprised of from about 30 to about 70 weight percent of the sheet material of synthetic polyolefin pulp, from about 15 to about 65 weight percent of the sheet material of inorganic alkali resistant filler, and from about 1 to about 35 weight percent of the sheet material of a long synthetic fiber, at least some of which is water swellable vinyl alcohol polymer.
Dependencies are inferred from the claim text.