A guy I know just bought a Gen 4 2016 Prius. He said the battery has a lifetime warranty. Is this new and just for the Gen 4 Prius or is it for all of them?
Toyota Motor Sales, U.S.A., Inc. has a Federal warranty of 8 years/100,000 miles and a CARB state warranty of 10 years/150,000 miles. http://www.toyota.com/t3Portal/document/omms-s/T-MMS-Prius/pdf/2016PriusWSG.pdf I do not know what other organization may have offered him a warranty. (you do not state your location, so no 'right answer' can ever be given you.)
Could be lifetime for battery but $3000 to install just like lifetime roofing materials but that doesn't cover installation. They probably replace 1-2 cells vs brand new battery. Run you $2000-3000 for Platinum Warranty package. Better read the fine print.
Most aftermarket warranty outfits don't cover the hybrid battery at all. When they say "battery" they mean the 12V.
Just read mine for the 2012 and the traction battery is excluded in the Platinum Toyota official warranty.