217
Repairing the Steam Deck LCD Gets Much More Expensive as Official Battery Reaches $180
(www.eteknix.com)
This is a most excellent place for technology news and articles.
Often the charge controller isn't even part of the battery. A BMS is but that is only a safety precaution against overcurrent or over/undercharge.
The charging itself, from the usb cable to the battery is usually done elsewhere.