The problem is likely cost effectiveness compared to just replacing a whole group of cells, compared to one single cell. The unit economics of getting the remaining life from single used laptop battery are not very good. There's certainly lots of potential value for someone willing to do the work, if they can afford the opportunity cost, or if a business can source extremely dirt cheap cells and cheap high skilled labor.

You would be amazed how many battery packs are multiple 18650s in a trenchcoat. Even EV battery packs use them. Though it does raise the question - wouldn't an old EV battery be a better solution than stripping apart laptops?

There is a lot of liability in sticking your name on a hodge podge of random used lithium cells.

Yes, with cheap third world labour, the same way many other technological marvels of the modern era are "automated".

You would never do this in a production product. You need batteries with similar internal impedances or undesirable things happen. This is the battery equivalent of the guy who welds two car front ends together and drives it around. It's cool and quirky but not a useful product for most people.

From what I've heard, it is more economical to recycle the raw materials than to reuse small packs.

Reuse of vehicle sized packs seems to be pretty common, though. I'd guess that a DIY home backup could be built pretty easily from used vehicle batteries.

Buying a used Nissan Leaf and using V2H feature in CHAdeMO is it. Or you can remove and use its well-reverse-engineered minimum nominal 24kWh semi-removable battery. But no one wants a Leaf, so there's that.

Of course, but you will also 'scale' the safety implications.

Standardizing battery packs would probably help with the automation; like with USB-C.

Isn't the problem with parasitic charging? Suppose you had a bunch of used 18650 cells. To scale the electronics, they'll be wired up in parallel and/or series so the charging logic can be shared, but since the batteries are wildly mismatched, it results in parasitic charging.

But will the scale justify the huge investment?