What happens when millions of electric car batteries get old? (opens in new tab)

That response seems a bit too dismissive when the entire OP is about how recycling capacity/capability for these items is sorely lacking. Many things that are much easier to recycle, for which the technology to do so already exists, are in fact not recycled because it's not economically viable. Why would it be any easier for items full of volatile and/or toxic components? Responses which amount to "magic it away" without even addressing the question of how to solve or avoid the various technological and economic problems are incurious and non-constructive.

Yeah, they go to https://www.redwoodmaterials.com/ or similar. Probably grid -> Redwood.

This is not yet a completely solved problem but by the time it's serious it will be solved.

They won't be recycled if its cheaper to manufacture new.

With Prius batteries, there’s a whole refurb scene where people buy the whole pack, crack it open, find the underperforming cells, and replace those. And that’s for a very small battery. So I would guess the same will be done for EV packs, since “most of the time” the cells will wear unevenly and the whole pack won’t be bad at once. If you do need a pack replacement after 10 years though, you probably get more power and range and lighter weight, so you get an upgraded car at the same time.