It adopts the mine intrinsically safe explosion-proof structure, and the charging and discharging switching of the backup power supply is managed by the single-chip system intelligently. The internal balanced charging method is adopted, which has the characteristics of small size, light weight, easy installation, safety and reliability. This power box adopts the circuit structure of parallel sampling and series protection, and has a double output short-circuit protection function to ensure that the matching equipment is not damaged when the power fails. It is suitable for powering intrinsically safe equipment in dangerous environments such as gas and coal dust in coal mines.