Electrical separators for batteries, especially lithium batteries, having
a shutdown mechanism. A process for their production. An electrical
separator is used in batteries and other systems in which electrodes have
to be separated from each other while maintaining ion conductivity.
Safety is very important in lithium batteries, since in contrast to other
types of battery (Pb, NiCd, NiMeH) the solvent for the electrolyte is not
water but a combustible solvent. A separator for lithium cells must
possess a shutdown mechanism while not being able to melt down. This is
achieved by an electrical separator having a shutdown layer which
comprises particles which melt at a desired temperature, close the pores
of the separator, and so stop ion flow. Since the separator also
comprises a porous inorganic (ceramic) layer on a carrier, the cells
cannot melt down as a result of a completely melted separator.