Please pardon me if I'm being thick, but is this actually an April Fools' joke? or is it real?
Because I do know that multi-cell LiPo batteries have a tendency to catch fire. If they have multiple cells in the pack, then if they become too unbalanced, they are liable to go up in flames. But I also know that most mobile phones use a single cell. Those are fairly hard to kill.
Have you considered LiFePO4 cells? One of those can withstand far more abuse than a LiPo. The drawback is that they have far less capacity than LiPos.
And for ideas on how to fix the heat problem(if it's real) I'd think there would be tonnes of ideas in these forums.