15-20 years depending on usage. Mostly, EV manufacturers are very comfortable offering 8 years or 100K miles on their batteries (whichever comes first). Meaning they don't anticipate failures to be a regular thing before that; or long after that. Most batteries should last a lot longer.
Most EVs produced ever (i.e. in the last 15 years) are still driving with their original batteries. So that should build some confidence. Some early cars with relatively primitive battery management obviously are getting their batteries replaced. But even then, it's not going to break the bank and extends the lifetime of the vehicle by a decade+. A 4K battery replacement for a 12 year old Nissan Leaf to double its range doesn't sound like a horrible deal, for example. Replacing a 20kwh battery with a 40kwh one for that money is a good deal and extends the life of the vehicle by about 10+ years.
Of course it all depends on battery chemistries and battery management. There has been a lot of improvement on both dimensions. Mostly I don't think there will be a lot of surprises on this front as this is a well studied thing.
And they were (still are?) having supply issues. My family ended up buying a Tesla last year instead of replacing a Nissan Leaf battery because the waiting list was something like six months long.
Most EVs produced ever (i.e. in the last 15 years) are still driving with their original batteries. So that should build some confidence. Some early cars with relatively primitive battery management obviously are getting their batteries replaced. But even then, it's not going to break the bank and extends the lifetime of the vehicle by a decade+. A 4K battery replacement for a 12 year old Nissan Leaf to double its range doesn't sound like a horrible deal, for example. Replacing a 20kwh battery with a 40kwh one for that money is a good deal and extends the life of the vehicle by about 10+ years.
Of course it all depends on battery chemistries and battery management. There has been a lot of improvement on both dimensions. Mostly I don't think there will be a lot of surprises on this front as this is a well studied thing.