1. EXTERNAL THERMAL DAMAGE – LiPo cells will get damaged by external heat. Most manufacturers recommend keeping the cells under 60 deg C or 176 deg F. In my experience, a cell will start to balloon up and the layers start to delaminate once the temperature rises above 90 deg C (194 deg F). If the temperature is extremely severe – the cell will go into thermal runaway and you will have a flaming mess. The thermal volatility is directly related to the cell chemistry. LiCoO2 is the industry standard and unfortunately, the most volatile. LiFePO4 (used in most power tools) is the least volatile and LiMnO4 Spinel (used by Apogee) is somewhere in between. Many of the responsible LiPo manufacturers are using mixtures and additives to LiCoO2 to decrease volatility at the expense of voltage output. Unfortunately, most manufacturers still use pure LiCoO2 since it seems to make the most power.