12 v40ah high-magnification lithium iron phosphate batteries, and 40 ℃ under extreme conditions, 0.2 C/C discharge efficiency is above 90%, 0.5-50 ℃ to + 70 ℃ temperature range interval, applied in the military field, outdoor detection, deep-sea diving (lighting), field electric tools, shipbuilding industry, high-speed train, etc., products used for cold and extreme weather conditions, and has high requirement to the electric current, long cycle characteristics.