A cooling system for a fuel cell system is provided with a circulation
system including a circulation pump for circulating coolant, the coolant
essentially consisting of water and glycol, a fuel cell connected to the
circulation system so as to be cooled by the coolant, a heat exchanger
connected to the circulation system so as to radiate heat from the
coolant and a filter connected to the circulation system and configured
to remove oxidation reaction product of the glycol from the coolant.