for your request, you can get it in Facebook group named "BAFANG eBike". Not sure if it's a good timing to take it as BAFANG's new arrivals always comes with some minor issues.
this is the battery, and the only power source on the bike. TBH, I think the design is nice. BTW, there are conversion kits company offering this bottle battery, too.
CEF50 starts from 17.75KG according to the suppliers. They have the battery option 43v 11.4ah at 2.6kg. It's a great choice to get a super lightweight emtb.