For many electric vehicles, there is no way to repair or assess even slightly damaged battery packs after accidents, forcing insurance companies to write off cars with few miles — leading to higher premiums and undercutting gains from going electric.

And now those battery packs are piling up in scrapyards in some countries, a previously unreported and expensive gap in what was supposed to be a "circular economy."

"We're buying electric cars for sustainability reasons," said Matthew Avery, research director at automotive risk intelligence company Thatcham Research. "But an EV isn't very sustainable if you've got to throw the battery away after a minor collision."