Cu-, Cu- and Ni-brazed stainless steel heat exchangers for fuel cell cars

摘要

In alternative propulsion vehicles also heat exchangers are needed for cooling. Behr is engaged in developing these components for fuel cell cars. In this presentation first the principle of a fuel cell car with its different heat exchangers is laid down. Then the structure of a so-called stacked heat exchanger, composed of a channel and a separation sheet made of stainless steel is explained. The manufacturing of the brazed prototypes is laid down. Au-and Cu-braze is applied by galvanising. The application of Ni-paste by screen printing on the seperation sheets is shown. After assembling the sheets to a heat exchanger the part is brazed in a vacuum furnace. The resulting joints are presented and discussed. Stacked heat exchangers proved to be good cooling devices for fuel cell cars.