The types and properties of separat

The types and properties of separators used for lead–acid batteries are reviewed. Attention is focused on the pocket-type polyethylene (PE)
separator as this is widely used in present-day automotive batteries, i.e. in low-maintenance batteries with expanded lead–calcium grids. An
improved PE separator has been developed by using a PE resin of high molecular weight. The resistance of the separator to attack by hot
sulphuric acid is increased by a factor of 1.5. Batteries using the improved separator show a 40% increase in lifetime under the SAE 75 8C lifecycle
test.