TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compounds: The power fuel is sodium borohydride (NaBH4) or potassium borohydride (KBH4). The electrolyte is sodium hydroxide (NaOH) or potassium hydroxide (KOH).    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: The fuel storage unit includes a fuel tank (110) where a power fuel and water are contained; and an electrolyte reservoir for containing electrolyte aqueous solution. It is formed as one fuel tank where a power fuel, water and electrolyte aqueous solution are contained. The fuel circulation supply unit includes a first line (310) for connecting the fuel tank and the anode of the DBFC; a gas/liquid separator (320) for separating a byproduct generated at the anode of the DBFC after a reaction into gas and liquid; a second line (330) for connecting the gas/liquid separator and the fuel tank and guiding a liquid byproduct of the gas/liquid separator to the fuel tank; a fuel pump (340) mounted at the first line; a recycle pump (350) mounted at the second line; and an electrolyte supply unit for supplying an electrolyte to the anode of the DBFC. The electrolyte supply unit includes a third line (371) for connecting the electrolyte reservoir and the first line; a three-way valve (372) mounted at a portion that the first line and the third line are connected to each other, for controlling a flow direction of a fluid; and a fourth line (373) for connecting an outlet of the cathode of the DBFC and the electrolyte reservoir. The electrolyte reservoir is provided with a first purge valve (375) for purging liquid contained in the electrolyte reservoir. The second line is provided with a first valve for preventing a fuel of the fuel tank from backwardly flowing to the gas/liquid separator. It is provided with a filter for filtering a solidified byproduct. The hydrogen controller includes a connection line (510) for connecting a gas/liquid separator constituting the fuel circulation supply unit and the anode of the PEMFC, and flowing hydrogen generated at the DBFC after a reaction to the PEMFC; a hydrogen reservoir (520) connected to the connection line, for temporarily storing hydrogen that flows through the connection line; a main gas valve unit mounted at the connection line between the hydrogen reservoir and the PEMFC, for controlling a hydrogen pressure as a certain degree so that hydrogen of the hydrogen reservoir can be supplied to the cathode of the PEMFC with a certain amount; and a hydrogen conduit open/close unit for allowing/shielding a hydrogen flow into the hydrogen reservoir by a pressure difference between inside of the connection line positioned at an inlet of the hydrogen reservoir and inside of the connection line positioned at an outlet of the hydrogen reservoir. The hydrogen conduit open/close unit includes a first pressure sensor (531) mounted at the connection line positioned between the gas/liquid separator and the hydrogen reservoir, for sensing a pressure; a second pressure sensor (532) mounted at the connection line between the main gas valve unit and the hydrogen reservoir, for sensing a pressure; a second valve (533) mounted at the connection line between the first pressure sensor and the hydrogen reservoir, for controlling hydrogen flowing in the connection line; and a control unit for opening and closing the second valve by a pressure difference detected by the first and second pressure sensors. The connection line positioned between the first pressure sensor and the second valve can be provided with a first compressor (534) for compression-pumping hydrogen. The main gas valve unit includes a third valve (541) mounted at the connection line between the hydrogen reservoir and the PEMFC, for controlling a flow amount of hydrogen; a regulator (542) mounted at the connection line between the third valve and the PEMFC, for supplying hydrogen of a certain pressure to the anode of the PEMFC; a second discharge line connected to the connection line between the hydrogen reservoir and the third valve; and a relief valve (544) mounted at the second discharge line, for controlling a pressure when an excessive pressure is applied. A third discharge line (411) for discharging a byproduct after a reaction is connected to an outlet of the anode of the PEMFC. A second purge valve is mounted at the third discharge line. The air supply unit includes an air distributor (610) for distributing air; a first distribution line (620) for connecting the air distributor and the cathode of the DBFC; a second distribution line (630) for connecting the air distributor and the cathode of the PEMFC; an air introducing line (640) connected to the air distributor, for introducing external air to the air distributor; a second compressor (650) mounted at the air introducing line, for compression-pumping external air; and an air filter (660) mounted at the air introducing line, for filtering introduced air. The PEMFC is provided with a fourth discharge line (431) at an outlet of the cathode, for discharging a byproduct generated at the cathode after a reaction outwardly; and a humidity exchanger (432) for performing a humidity exchange between air introduced into the cathode and a byproduct discharged to outside is connected between the fourth discharge line and the second distribution line. The fourth discharge line is provided with an evaporator (433) for evaporating water discharged from the fourth discharge line.