Method of making a gas recombinant battery separator
OwnerMehrgan Khavariinventor
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Abstract
A recombinant lead acid battery separator formed of a PTFE fibril matrix and a particulate, amorphous silica filler enmeshed in the PTFE matrix. The separator has a tensile strength greater than 0.5 MPa, a bulk density lower than about 0.40 gram/cc and a void volume greater than about 75%. The separator is made by mixing together PTFE and a non-evaporative lubricant, adding amorphous silica during mixing, continuing mixing until a material having a dough-like consistency is obtained, removing the dough-like material and calendering it to form a sheet, removing from about 95% to about 100% by weight of the non-evaporative lubricant from the sheet by solvent extraction, and drying the extracted sheet.
Claims7
A process of making a battery separator for a recombinant lead acid battery comprising mixing together PTFE and a non-evaporative lubricant to form a substantially homogeneous mix, adding amorphous silica to the mix and continuing mixing under mechanical shear forces sufficient to fibrillate said PTFE, upon achieving sufficient fibrillation to form a dough-like mass subjecting said mass to calendering to form a sheet, removing between about 95% and about 100% by weight of said non-evaporative lubricant, and drying said sheet.
Dependencies are inferred from the claim text.