Patent ID: 7767325

Claim:
A method for the investigation of a fuel cell system, said fuel cell system having an anode side to which a fuel is supplied in operation and a cathode side to which an oxidizing agent is supplied in operation and comprising at least one fuel cell, each said fuel cell having an anode, a cathode and a membrane separating said cathode from said anode, said method comprising a first test comprising at least one of the following tests: a) to test whether said fuel cell system is gas-tight at said anode side and/or at said cathode side, b) to test whether a leakage is present, between said anode side and said cathode side, c) to test a starting behaviour of said fuel cell system, or d) to test an operation of said fuel cell system at low current yield, said first test being carried out with a mixture of at least one inert gas with a fuel permissible for the operation of said fuel cell system, said mixture being supplied to said anode side of said fuel cell system and the amount of fuel in the mixture being predetermined such that a proportion of said fuel present in said mixture lies below a value at which said mixture is flammable in air, and wherein said tests are conducted outside of a test chamber, wherein the mixture consists essentially of 95% N 2 and 5% H 2 .