Method for producing a heat exchanger module having at least two fluid flow circuits

A method for producing a heat exchanger module having at least two fluid circuits which each comprise channels, comprising the following steps:

• a/ producing one or more elements of one of the two fluid circuits, referred to as the first circuit, each element of the first circuit comprising at least two metal plates, at least one of which comprises first grooves;
• b/ stacking the at least two metal plates of each element so that the first grooves form the channels of the first circuit;
• c/ assembling by means of diffusion welding between the at least two stacked metal plates of each element of the first circuit;
• d/ producing one or more elements of at least one other fluid circuit, referred to as the second circuit, each element of the second circuit comprising at least a portion of the channels of the second circuit;
• e/ assembling by means of diffusion welding or by means of soldering, or by means of diffusion soldering, between the element(s) of the first circuit and the element(s) of the second circuit.