Our corporate offers only standard 6 cell battery for the Lenovo
X220 laptop that they issue out. If I want to get an extra battery,
is a 6 cell slice (think this must be a battery that's joined/added
to existing 6 cell battery ??) or a 9 cell (this one will require
existing battery to be removed for it to be inserted ??) will
offer continued/seamless (ie no disruption to laptop) power
between the 6 cell slice & 9 cell, which one offers longer extra
which of the two is lighter in weight & less bulky ?