The invention provides a fault diagnosis method for a fuel
cell system. The fault diagnosis method comprises the steps of executing offline
processing and executing on-line
processing; the off-line
processing is used for establishing a fault
database according to operation and fault data of a fuel
cell, collected by a plurality of sensors and calculating a fault threshold value; and the on-line processing is used for identifying the type of a fault according to the fault
database and the fault threshold value, judging the type of the fault according to the fault
database, if the fault is reversible and a fault component is a non-
core component, reconstructing a sensor
signal corresponding to the fault component to enable the fuel
cell system to continue running, and if the fault is irreversible or the fault component is a
core component, shutting down and maintaining the fuel
cell system. The method has the advantages that
signal authenticity
verification, fault diagnosis, fault positioning and fault-tolerant control are realized, and
signal reconstruction is realized through an
algorithm to maintain
power output in a fault state, so that the safety and reliability of the fuel cellsystem for a vehicle are ensured; and the method can be suitable for different fuel cell systems.