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I ran a LiFePO4 pack for years in Vermont winters and had no problems with it, even on those days where it was subzero - but I had a supercapacitor pack in parallel that took nearly all of the pulse current. The pack really should not have survived what I put it through. This is just speculation, but I'd wager the colder it got, the higher the pack's internal resistance, and the more the supercapacitors took the load and the less discharge and subsequent charge the pack got.
As for the cells linked, I'm not sure what tricks they have used to make it safe to charge the chemistry below freezing, but the key thing here is really charge rate vs temperature - the lower the charging temperature, the lower your charging current needs to be to not form dendrites. Double the cells in the pack and you cut both the charge and discharge current (per cell) in half. A bigger pack will survive longer.
One trick some people have tried is using other lithium chemistries. The Fit Hybrid shipped with a lithium titanate pack which is basically impervious to cold or heat, and people buy those and tear them apart to make smaller packs. Just gotta watch out with different chemistries is nominal voltage, which is not the same.
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