Fuel cell system and method for operating the same

A fuel cell system comprising a fuel cell (2) comprising an anode with a fuel feed line to feed fuel to the anode (2.1) and an anode exhaust line (4) for removing anode exhaust from the anode, a cathode (2.2) with an oxygen feed line (5) to feed oxygen to the cathode and a cathode exhaust line (6) to remove cathode exhaust from the cathode, a compressor (7) arranged in the oxygen feed line for feeding oxygen to the cathode and a cooling circuit (10) for cooling the fuel cell, where a fluid connection (12) is arranged between the oxygen feed line (5) downstream the compressor (7) and a coolant tank (8) in the cooling circuit.