To improve the safety and reliability of local ventilation of heading face in the coal-mine and prevent gas accumulation effectively, the paper develops a flameproof 660V- high power three-phase emergency power supply (EPS) for auxiliary fan in the mine. The paper illustrates the design and implementation of the battery system which is the core of the EPS, including the design of constitution of high-voltage battery, high power charging power supply, charging circuit based on PLC, and circuit for charging protection and equilibrium of batteries.