on thier page near the bottom they have a CAUTIONS section where it clearly states that you need a PCB with over charge, over discharge, over drain and short circut protection.
If you DIY by yourself, you MUST install Our PCB or your own PCB with the following feature:
◦4.2V/cell over-charge protection
◦2.5V/cell over-discharge protection
◦Max current over-drain protection
◦Short circuit protection
so it is RECOMMENDED that you use a PCB to provide those features.
now with that said... the battery would be OK to use, but you are giving up many safety features by not using a protected battery. and while many people (myself included) are using non-protected
batteries such as the CR2 in both home-made and commercial mods, i would not recommed that anyone do this because of the risk of exploding
batteries.
since the 14650 should be available in a protected version i would search for one that is protected
before doing any oredering i would suggest that you read up on the stickie threads in the battery mod section and pay extra close attention to the posts about EXPLODING
batteries.
i learned alot reading these threads last night...
RAOR of the Pelican this link involves PROTECTED batteries that exploded while in use!!
Lithium Battery Failure
**BOOM!** Battery Failure
The ABCs of batteries
those links will help get you started.