Life expectancy for 2013 Volt battery.

I'm trying to find some solid estimates on how long the batteries last on these and finding absolutely nothing useful. One place will say people have run 400k miles without a single issue. Others say they only last 5 years (which is absurdly obviously wrong). Just estimates all over the place, and I have no real idea. So, Volt owners, any estimates for me?

EDIT: Thanks so much to those contributing. I really appreciate the answers.