lithium-ion battery in a climate-controlled storage structure, such as a shed or garage, or take it inside your house for storage. Lithium-ion batteries handle cold temperatures – down to 14 degrees Fahrenheit – better than warm temperatures. Extended time in a temperature above 85 degrees Fahrenheit can harm the battery's performance.
Concerned about your mower's battery? Explore whether a bad solenoid can drain a lawn mower battery and get the answers you need in this article.
greenryenthusiast.com
Umm I think you are getting your units mixed up here
Li batteries are good down to -15 C after which they freeze which destroys the separators
They will work most efficiently in the 0 to 10 C range after which their performance starts dropping off
Depending upon the exact structure & chemistry most will self ignite between 80 & 90 C
Once ignited they can not be extinguished as the residents of Cal have just found out .
They were lucky that the fire control system worked properly and only 1 pack went up although they are not releasing any more details one source says that more than a 1/2 dozen were damaged beyond repair