ESTIMATING COOLANT CONDUCTIVITY IN MULTI-VOLTAGE FUEL CELL SYSTEM WITHOUT DISCONNECTING CONTACTORS

摘要

PROBLEM TO BE SOLVED: To provide a system and method for monitoring the conductivity of a cooling fluid flowing in a fuel cell system on a vehicle including a chassis.SOLUTION: The fuel cell system includes a fuel cell stack electrically coupled to a stack bus, and a battery electrically coupled to a propulsion bus. The method includes operating the fuel cell system, measuring a first isolation resistance at a first power level, measuring a first stack voltage, and measuring a first battery voltage. The method also includes operating the fuel cell system at a second power level, measuring a second isolation resistance, measuring a second stack voltage, and measuring a second battery voltage. The method further includes calculating a stack coolant resistance using the first and second isolation resistances, the first and second stack voltages and the first and second battery voltages, which is then used to calculate the cooling fluid conductivity.SELECTED DRAWING: Figure 2