Looks like the Focus uses lithium polymer cells:
http://www.compactpower.com/bpack.shtml
http://www.compactpower.com/bpack.shtml
Improved calendar life, a must have in the Lithium battery industry.1) Safer chemistry (without compromises in performance or life) - specifically LG Chem/CPI use manganese-based cathode chemistry with additives to improve calendar life under high temperature conditions