Battery System and method has fuel to make it work

The invention relates to a system (1) for fuel cells which comprises a stack (3) of fuel cells, a heat exchanger (33) forming cathode recuperator designed to heat an air inlet stream using heat from a cathode exhaust stream of the stack of fuel cells, and a heat exchanger (39) forming an air preheater which is designed to heat the air inlet stream using heat from an anode exhaust stream from the stack (3) of application combustible.Domaine cells: fuel cells of solid oxide type, etc.