http://www.greencarreports.com/news/1098989_u-s-electric-car-battery-industry-could-grow-if-supply-base-matures

Even for U.S.-assembled lithium-ion cells like those now used in the U.S.-built Nissan Leaf, the high-value electrode material is still imported--in this case from Japan--which significantly lowers the car's domestic content.

Costs for U.S. manufacturers are also generally higher than in other countries, the report found. Analysts found China, South Korea, and Mexico to have the lowest average costs.