"Based on discussions with industry experts and several automakers, the DB Auto team has lowered its advanced lithium ion battery cost projection by about 30% for 2012. Current prices have fallen from $650/kWh+ in 2009 to about $450/kWh now, and DB’s forecast is the price to fall at about a 7.5% CAGR from 2012 through 2020 to about $250/kWh."
And lots others on Google. I don't know enough about it to judge who is credible but I do believe that laptop batteries don't cost as much as they used to. It's not like Moore's Law, but I think prices have been falling pretty steadily.
