I couldn't find anything definitive but I've quoted a couple of short blurbs below. Can't vouch for the sources so don't take it as gospel. If you're really concerned you should try contacting Mooch and asking him the safe temp range of a Li-ion battery. Bottom line for me is that a torn wrapper absolutely has to be replaced and that process does need some heat.No but hot enough that I worry about the health of the battery
Most lithium-ion (Li-ion) cells must not be charged above 45°C or discharged above 60°C. These limits can be pushed a bit higher, but at the expense of cycle life. In the worst case, if cell temperatures get too high, venting may occur, resulting in battery failure or even a cell fire.Jul 29, 2009
The use of a lithium-ion battery is possible in a temperature range of 10°C to +55°C. However, the charging should take place only at a battery temperature of +5°C to +45°C. The deal temperature range of the batteries is room temperature.