I think there'll be an economic incentive for at least miniaturizing battery cells, while keeping capacity. Even if there is a limit to EV range, where consumers simply won't be interested in cars that go much further, reducing the weight of the battery itself, will be a direct economic boon for the consumer. There might also be some unforeseen boons to cheaper and lighter batteries, kind of how the personal drone market sprung out of the advances made in lithium-ion batteries for Smartphones/Laptops.