Fault diagnosis device and method of fuel cell system

The invention relates to a fault diagnosis device and method of a fuel cell system. The fault diagnosis device comprises a communication unit, a diagnosis core unit and a man-machine interaction unit and is characterized in that the communication unit is used for receiving the procedure parameters and working condition information of a main controller as well as the single cell voltage information of a monitor unit and sending diagnosis results and various parameters and data to a field remote control monitoring center and an upper computer; the diagnosis core unit is used for detecting and positioning the faults of the sensor, actuator, controller, monitor unit and galvanic pile of the fuel cell system through the formulated diagnosis strategy; and the main-machine interaction unit is used for displaying, setting, clearing and modifying the diagnosis results and providing maintenance suggestions and measures. By considering the electrochemical reaction mechanism of fuel cells, combining the knowledge and experience of experts and adopting a multisensor information fusion method, the device can be effectively applied to the long-range, short-range, off-line and online fault diagnosis of the fuel cell system, thus the fault diagnosis accuracy and maintainability are improved.