Lol assuming this is an honest question, or answering for those that are truly wondering, 18650 is a type of battery, not the count. Like AA, AAA, etc.
If you already opened it to install this, why didn't you just buy an actual replacement from China?
ETA:
This is (probably) a Blackview Tab 12 Pro
I found a proper replacement ranging in price from $10 to $30 depending on if you wanted a Stateside store and faster ship or willing to wait for AliExpress.
It is very unique for sure, I don't think I've ever seen this done on a tablet before!
I worry about being able to take the tablet outside the house without getting the bomb squad called on you, but I suppose you could maybe 3D print a cover for it, maybe even integrate a kickstand for that extra functionality lol
the only difference between this and the internal one is that its more sucepptible to piercing damage, but the contraption itself isnt any more inherently dangerous conpared to the battery in the tablet itself.
if youre worried about house fires at all one shouldnt even use lithium ion batteries period.
Well except for the exposed contacts from the holder. These types of holders are designed to be on the inside of things and not exposed. Bridging one side to the other would be a fire and explosion risk. OP needs to put a cover over it to be safe, or at least some kapton tape over the exposed contacts.