NOVELTY - The method comprises placing a first element (16, 18) and a second element (10) one on the other, and connecting the elements by a solder material, which is subjected to ultrasonic vibrations during joining by a tool (32, 34) such as a sonotrode. The first element comprises through-passage openings (28, 30) for joining the first element with the second element, and the first and second elements are placed one on the other with through-passage openings. The solder material is supplied to a gap extending between a heater (40, 42) and the tool, and is melted.    USE - The method is useful for the cohesive connection of a first element such as an electrically conductive connector including a cell connector to a second element such as a semiconductor device including a solar cell with front and back sides or a current conductor of a solar cell (claimed).    ADVANTAGE - The method ensures effective connection of the first element to the second element in an energy efficient manner.    DETAILED DESCRIPTION - The method comprises placing a first element (16, 18) and a second element (10) one on the other, and connecting the elements by a solder material, which is subjected to ultrasonic vibrations during joining by a tool (32, 34) such as a sonotrode. The first element comprises through-passage openings (28, 30) for joining the first element with the second element, and the first and second elements are placed one on the other with through-passage openings. The solder material is supplied to a gap extending between a heater (40, 42) and the tool, and is melted. The molten solder material is: located in the through-passage openings during the joining process; and subjected to the ultrasonic vibrations in the through-passage openings. The sonotrode flows through the gap along the end surface of the tool. Before placing the first element on the second element, the solder material is applied on the first element corresponding to an arrangement of the through-passage openings. A portion of the tool or its side face is immersed in the through-passage openings during the cohesive joining process. The cohesive joining process is carried out along a perpendicular line passing through the openings. A unit for forming superposed first and second elements is resiliently supported in the direction of a workpiece, and/or the workpiece is resiliently supported in the direction of the unit during the cohesive joining process, where the unit is transported during the joining process and the tool is movably or fixedly arranged. The first element is a solder free connector made of aluminum or an aluminum-containing connector. The tool and the heater are heated to a temperature above the melting temperature of the solder material, where the temperature of the heater is independently set by the temperature of the tool.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an assembly for cohesive connection of a first element to a second element.    Second element (10)    First element (16, 18)    Through-passage openings (28, 30)    Tool (32, 34)    Heating device. (40, 42)