Heat exchanger system for operating a fuel cell stack

A heat exchanger system (100, 200, 300, 400, 500, 600, 700) for operating a fuel cell stack (190), the heat exchanger system comprising:

• a first compressor (142) and a second compressor (150) for cathode gas supplied to the fuel cell stack (190), wherein the second compressor (150) is arranged fluidically downstream of the first compressor (142);
• a turbine (155), which is mechanically coupled to the second compressor (150) and against which cathode gas discharged from the fuel cell stack (190) flows;
• a first heat exchanger (110), which is thermally coupled to the supplied cathode gas between the first compressor (142) and the second compressor (150);
• a second heat exchanger (120), which is thermally coupled to the supplied cathode gas downstream of the second compressor (150);
• a fourth heat exchanger (140), which is thermally coupled to the discharged cathode gas downstream of the turbine (155);
• wherein
• the fourth heat exchanger (140) is thermally variably coupled to the first heat exchanger (110) and to the second heat exchanger (120) in order to control a heat exchange for cooling the first heat exchanger (110) and the second heat exchanger (120), and
• the fourth heat exchanger (140) is thermally variably coupled to both the first heat exchanger (110) and the second heat exchanger (120) by means of a coolant and a first three-way valve (161) in order to cool the supplied cathode gas upstream and downstream of the second compressor (150).