Seems Yamaha have a semi open standard, with some of the companies that integrate their tech building their own batteries.

I ride a seven year old Bosch CX, the internet says that any battery that fits the mount works, the supplier says it needs to have the same ID or it won’t.

There was an article around a few months back about a startup that builds replacement focused bike batteries. Part of the article was how much of a pain it was to reverse engineer the Bosch battery communication but they claimed they did it and that other brands were far easier. Couldn’t find it anymore unfortunately.