Lithium Boom Only Just Begun A 20-Year Bull Run, page-27

For those who don't know what a seperator is in the world of Lithium,well here is an explaination.
What is a separator?
A separator is
essentially
a piece of plastic, but that understate
s its crucial role in the functioning of a
battery. The separator is
a porous piece of material
(typically either polyethylene or polypropylene)
that allows for lithium ions to flow between the anode and cathode of the batter
y as well as preventing
the sho
rt circuiting of the electrochemical process
(separator
s
are also used in lead acid batteries)
.
The thickness of a separato
r is measured in microns. One micron is one millionth of a meter or
.00004 inches. A human hair is roughly 75 microns across and the
typical separator is 25 microns
and below depending upon a host of factors.
Given that batteries can generate a great deal of heat during usage and charge cycles, the separator
effectively “shuts down” the battery
when the temperature reaches 130° C (266°
F)
by melting and
closing the microscopic pores
, blocking ion transfer
in the electrolyte
.
Battery chemistry hinges on
safety more than any other issue and so preventing the excessive heat, also known as thermal
runaway is imperative.