Heat transfer device and heat transfer preliminary product assembly and method for manufacturing such a heat transfer device

The heat transfer device has an inner housing (2) which has housing parts (12,14), whose base surfaces (16,18) are arranged at a distance from each other. A weld seam (44) is formed at the base surface of the latter housing part. The weld seam is extended to an end (26) of a partition wall (22) by the base surface of the former housing part such that the partition wall is fixed at the latter housing part over the weld seam. An independent claim is also included for a method for manufacturing a heat transfer device.