Tedla are talking about their batteries lasting 1 million miles and many manufacturers are suggesting the battery will outlast the car.
That’s because unlike most people, they understand how their batteries work and that this claim is complete nonsense.
This is marketing. Of course a car battery lasts a million miles. The more interesting question is, how many (fast) charging cycles does the battery withstand without degradation. Batteries mainly degrade through charging/over-discharging. That’s why you get told to not charge over 80% capacity, and not drive it down to 0%. So, if you take charging out of the equation, yeah, they’ll hold for a million miles.
And yes, ALL EV batteries outlast their cars. They don’t get scrapped, but re-purposed. Even batteries that hold less than 50% charge, and in low current applications they’ll last for another 30 years. But not as a propulsion battery for a car, because they’d be too damaged for that.
It’s probably reasonably safe to buy a “new-ish used car”, not older than maybe 5 years. Everything above, you certainly should put money aside for a new battery, because the main issue is that you can’t judge the battery by A: a short test drive or B: by looking at the mileage. The mileage is barely an indicator for battery condition. If given the opportunity, i can bring an EV battery below 70% capacity within the warranty period and not have even 15.000 miles on the clock.
Prior: SEAT Ateca Xcellence Lux 1.5 TSI DSG MY19, VW Golf GTE PHEV DSG MY23
Current: Hyundai Ioniq 6 Ultimate
Next: we'll see what's available in 2028.