Patent ID: 8053126
Filing Date: 2011-11-08
Classification: H01M,Y02E,Y02T

Abstract:
1. A fuel cell system comprising: a fuel cell stack including a cathode inlet line and a cathode outlet line; a compressor for providing cathode inlet air to the cathode inlet line; a first charge air cooler for reducing a temperature of the cathode inlet air from the compressor; a water vapor transfer unit for humidifying the cathode inlet air traveling through the cathode input line, said water vapor transfer unit receiving a cathode exhaust gas from the cathode exhaust gas line for providing humidity for the cathode inlet air; a heat exchanger for reducing a temperature of a stack cooling fluid flow sent to the first charge air cooler to cool the cathode inlet air, said heat exchanger receiving ambient air for cooling the cooling fluid; and a valve assembly for by-passing the cooling fluid on a by-pass line around the heat exchanger, said valve assembly being controlled so that the heat exchanger is by-passed if a relative humidity of the cathode inlet air is at or above a predetermined RH set-point and sending the cooling fluid to the heat exchanger if the relative humidity of the cathode inlet air is below the RH set-point.