The invention relates to the technical field of
fuel cells, and especially relates to a fuel
cell system bleeder circuit based on two-stage protection. The circuit comprises a fuel
cell stack, a fuelcell boost DCDC module, a finished automobile high-
voltage power distribution box PDU and a bleeding heater, the fuel
cell boost DCDC module comprises a DCDC boost circuit, a DCDC input side main
relay K2 and a DCDC output side main
relay K5, the output end of the fuel cell stack is connected with the DCDC boost circuit through the K2; the DCDC boost circuit is connected with the input end of thefinished automobile high-
voltage power distribution box PDU through the K5, the fuel cell boost DCDC module comprises a
discharge relay K3 and a PTC power supply relay K7, the output end of the fuel cell stack is connected with the input end of the bleeding heater through the K3, and the K5 is connected with the input end of the bleading heater through the K7. A traditional
bleeder resistor is omitted, a load PTC heater is directly utilized, and the boost DCDC space and cost are saved. And meanwhile, the requirement for rapid bleeding can be met, and the emergency shutdown time of a fuel cellsystem is saved.