Patent ID: 8486571
Filing Date: 2013-07-16
Classification: H01M,Y02E

Abstract:
1. A method for controlling output of a fuel cell in a fuel cell hybrid vehicle including a fuel cell as a main power source and a storage means as an auxiliary power source, the vehicle having a power converter disposed between the fuel cell and the storage means and provided for a constant current operation of the fuel cell and a directly connected switch for directly connecting/disconnecting the fuel cell and the storage means, the method comprising: controlling an output of the fuel cell according to an amount of electrical energy already stored in the storage means by switching between a fuel cell stop mode, a fuel cell constant current mode and a fuel cell storage means direct connection mode wherein power generation of the fuel cell is stopped in the fuel cell stop mode, the power converter is operated so that the fuel cell is operated at a constant power at a maximum efficiency point in the fuel cell constant current mode, and the fuel cell and the storage means are directly connected by the directly connected switch and then the output of the fuel cell is controlled according to a load required by the vehicle in the fuel cell-storage means direct connection mode, wherein, if the amount of electrical energy of the storage means is below a reference value for restarting the power generation of the fuel cell and if the elapsed time after the fuel cell stop exceeds a predetermined minimum retention time in the fuel cell stop mode, the fuel cell stop mode is switched to the fuel cell constant current mode in a state where the directly connected switch is turned off.