Hi Kevin,
the question is actually focusing more on the first and second life cycle of the battery. As you take the batteries from acidented cars, their first life cycle is already "done" and you need to think if the second life cycle gets any burden from the first one (it is a "reuse" case). I would recommend you to have a look at scientific literature how they solve it. If arrive with zero burden for the second life cycle, your battery arrives with no environmental impacts but collection, repurposing, operation, and end-of-life hold impacts. Hope this helps