Also, I've mentioned this on hn before, there is already the Cordless Alliance, which does exactly this.
Sadly, there's only a couple of useful-in-a-mainstream-sense brands in there: Mafell and Metabo. The rest are very niche.
Good on Metabo for doing it, and good on Mafell for signing up to use them. The smaller brands it's a no-brainer I guess.
Personally I'd be happy for that situation because of the big upside, but I can see why a company would not want it.
Plus, the most logical thing to do is not make a new standard, but pick an existing one. But who gets to be the golden brand whose battery system remains unchanged?
I would love it to happen but I can't see it happening for a while.
The first one to make all relevant patents & designs available royalty-free.
Perhaps part of a battery standardisation push could include making these available at a reasonable price.