I watched this last week and was blown away at how useful "used" cells could be in the right hands. Also, imagining what low skill labor looks like a battery offset world.
I am not sure whether the same idea could be applied to a car battery with much more advanced battery management systems, since in those situations dead cells don't cripple the battery, so the other cells keep getting used until they lose efficacy. So I suspect cells scavenged from car batteries will be of lesser quality than those scavenged from laptops.
Not totally sure if I have it right.
Think something like a conversion kit that turns your Model 3 battery pack that you've removed from your car into a powerwall.