The battery pack for the Volt is possibly the most important part of the car.  It’s the most expensive component, and if it malfunctions the car loses almost all of it’s appeal (assuming it doesn’t cause a fire in which case the car loses all of its appeal).

LG Chem is going to be the supplier for the lithium ion batteries used in the Volt, but GM is going to be the assembler of the actual battery pack.  I don’t blame them either, from a quality control standpoint and a liability standpoint GM wants to be in charge there.  It would be a PR nightmare to tell the owner of a Volt that they have to talk to a third party about their car.  So the batteries will be shipped to a plant in Michigan where the ‘T’ shaped battery pack will be assembled under GM supervision and control.