You're vastly overestimating the temperature sensitivity of lithium batteries. They explode due to short circuits (allowing the stored energy to be quickly con

You're vastly overestimating the temperature sensitivity of lithium batteries. They explode due to short circuits (allowing the stored energy to be quickly converted into heat, also heating the battery itself in the discharge process), not a simple warm-up to 60°C. For comparison, leaving your laptop (or cellphone) on a car's dashboard on a sunny day is more dangerous than this; with very bad luck (and dark colors) you can almost get water boiling there. (Quick googling says 90-95°C.) FWIW though the higher temperatures will degrade the battery quicker. . For reference: (tested at 130°C, safety limit at 100°C, operational up to 60°C) https://www.orbtronic.com/content/samsung-35e-datasheet-inr18650-35e.pdf https://www.orbtronic.com/content/samsung-35e-datasheet-inr1... 9.4 Heating Test Test method: To heat the standard charged cell at heating rate of 5°C per minute up to 130°C and keep the cell in oven for 10 minutes. Criteria: No fire, and no explosion. ... 8.7. Caution - The Battery used in this device may present a risk of fire or chemical burn if mistreated. Do not disassemble, heat above 100°C or incinerate. ... The battery can be used within the following temperature ranges. Don't exceed these ranges. Charge temperature ranges: 0°C ~ 45°C Discharge Temperature ranges: -10°C ~ 60°C Store the battery at temperature below 60°C