A method for manufacturing a double-wall heat-exchanger tube including an external tube and an internal tube, these tubes being metallic, cylindrical and coaxial. This method includes providing a first tube having an inside diameter d.sub.1int and an outside diameter d.sub.1ext, this first tube being intended to form the external tube, a second tube having an inside diameter d.sub.2int and an outside diameter d.sub.2ext, this second tube being intended to form the internal tube, and a cylindrical coaxial tubular leaf made from Fe.sup.0 having an inside diameter d.sub.int and an outside diameter d.sub.ext, such that 0.15 mm(d1intdext)0.25 mm, 0.15 mm(dintd2ext)0.25 mm, and 10 m(dextdint)200 m.

A method of making a heat exchanger that includes providing a plurality of tubes. Each of the plurality of tubes has exterior cladding on an exterior surface, interior cladding on an interior surface, and a weld seam extending along the length of the plurality of tubes. The method further includes arranging the plurality of tubes such that each of the plurality of tubes is inserted into a corresponding header slot with the weld seams of each of the plurality of tubes oriented downward with respect to gravity, and brazing each of the plurality of tubes and the header after each tube has been inserted into a corresponding header slot. The brazing causes the interior cladding to melt and pool inside the plurality of tubes and along an interior side of the weld seams to form a clad cover portion encases debris generated while forming the weld seams.

A welding device for a non-circular plate according to an embodiment includes a chuck for gripping and rotatably supporting a plurality of laminated non-circular plates, a welding torch for welding outer peripheral edge portions of the plurality of laminated non-circular plates, a stationary shield box, and a movable shield box which is position-adjustable with respect to the welding torch so as to form a shield space surrounding the welding torch with the stationary shield box.

A heat exchanger plate which has a plate body formed from at least two plate elements and at least one connecting piece for a cooling fluid. The plate body and connecting piece are joined together using soldering. The connecting piece has a joining portion which is joined in a receiving portion of the plate body formed between the plate elements. A solder resist limits the flow of solder when producing the solder connection. The solder resist is able to be formed by a sealing metal, which is arranged on the joining portion of the connecting piece in front of and/behind a solder material applied to the joining portion. The solder resist is able to be formed by an annular bead resting on the end face of the receiving portion.

A cooling plate for battery cooling has a plate body formed from two plate elements and a connecting piece for a cooling fluid. The connecting piece has a connection section which is joined in a receiving section of the plate body formed between the plate elements. The connection section has two arcuate wall sections in cross section and two opposing, outwardly directed longitudinal webs. The receiving section has longitudinal grooves extending between the plate elements in the area of the joining plane. The longitudinal webs run in the longitudinal grooves.