It's purely speculation but we also don't know if the GH can relieve pressure. So even if the battery does vent...
Edit: Ultrafire batteries are like the 1977 Ford Pinto's of the industry. I don't think GH could make such a shitty battery if they tried. Hopefully
Hopefully venting is part of the design, it's a well known issue, other vapes seem to be on board with it.
Ultralife might be low end, but the potential is a function of the technology, all such batteries have this potential. If you look under the positive terminal you can usually see the burst diaphragm (safety) through the vents. There's a LOT of energy stored there. This is why they don't let them on airplanes......no matter the brand.
Rest assured GH did not go into the battery making business, they like many others are no doubt contracting them out to an existing 'battery house'. The "threshold of entry" to the battery business (cost to make first articles) is huge, probably exceeding the GH total budget? Not to mention that battery production has the same 'rules' as vape production, IMO they would be waist deep in reject batteries if they were also 'breaking into that business'.
IMO this one's a clear "buy" in the classic 'make or buy' school. Best plan is probably COTS (Commercial, Off The Shelf), followed by a custom run from an established maker.
OF