GM is getting their cells from the LG Chem factory in Michigan. That factory was designed to initially produce enough cells for up to 50,000 Volts a year each having 288 pouch cells. The factory was designed so it could be rapidly expanded to produce enough cells for 200,000 Volts. The new Volt (and the Spark EV, which is supplied by the same factory) now uses 192 cells per car which might imply that the plant could now be expanded to supply up to 300,000 Volts per year ((288/192) * 200,000). Let's say it takes about 3x the cells in the Volt to make a 55-60 kwh pack (2016 Volt has 192 cells for 18.4 kwh so 3x would be 55.2 kwh). That implies that the existing LG Chem plant could be relatively rapidly expanded to support up to 100,000 200-mile cars or maybe 85,000 plus 45,000 Volts. That's not 500,000 cars a year like the GF at full capacity in 2020 but it's still plenty of cars. There are very few passenger car models that sell that well that are priced over $30,000. I would hardly call that "compliance car" territory.
Of course, if sales are that successful I'm sure LG and GM will be building out a new factory in short order. The original factory took a couple of years to build. And, of course, LG has other factories and could export enough cells to Michigan to fill the gap while they build a new US factory.
LG Chem To Set Up Michigan Battery Plant | TheDetroitBureau.com