A method and associated device for joining a battery cell tab to a plurality of foils associated with a plurality of electrodes of a battery cell are described. This includes arranging the plurality of foils in a stack, and joining, via a first joining device, the plurality of foils, wherein the first joining device defines a joining region. A portion of the battery cell tab is arranged on the plurality of foils, and joined, via a second joining device, to the plurality of foils. The second joining device generates a weld joint that is encompassed within the joining region defined by the first joining device. In doing so, weld quality and strength of internal welds in a battery cell may be improved by reducing the occurrence of porosities and cracks in the foil/tab weld joints.

A method and associated device for joining a battery cell tab to a plurality of foils associated with a plurality of electrodes of a battery cell are described. This includes arranging the plurality of foils in a stack, and joining, via a first joining device, the plurality of foils, wherein the first joining device defines a joining region. A portion of the battery cell tab is arranged on the plurality of foils, and joined, via a second joining device, to the plurality of foils. The second joining device generates a weld joint that is encompassed within the joining region defined by the first joining device. In doing so, weld quality and strength of internal welds in a battery cell may be improved by reducing the occurrence of porosities and cracks in the foil/tab weld joints.

A laser welding method is provided to ensure a sufficient joining strength between metal plates by increasing the area of a joining region while preventing “burn through” of a molten metal. In the laser welding method by applying a laser beam to a surface of multiple metal plates superimposed on each other, a scanning locus with the laser beam is sequentially shifted from an inner circular scanning locus to an outer one in a predetermined joining region on the metal plates, and an emission interval is provided to temporally stop the metal-plate-surface irradiation when the scanning locus is shifted. Thus, every time the scanning locus is shifted, the molten metal due to the previous irradiation is cooled and increases its viscosity. Accordingly, the “burn through” is prevented regardless of increase of the area of the joining region, which results in a sufficient joining strength between the metal plates.

A laser welding method is provided to ensure a sufficient joining strength between metal plates by increasing the area of a joining region while preventing “burn through” of a molten metal. In the laser welding method by applying a laser beam to a surface of multiple metal plates superimposed on each other, a scanning locus with the laser beam is sequentially shifted from an inner circular scanning locus to an outer one in a predetermined joining region on the metal plates, and an emission interval is provided to temporally stop the metal-plate-surface irradiation when the scanning locus is shifted. Thus, every time the scanning locus is shifted, the molten metal due to the previous irradiation is cooled and increases its viscosity. Accordingly, the “burn through” is prevented regardless of increase of the area of the joining region, which results in a sufficient joining strength between the metal plates.

Method for producing an active part (1) for a rotating electric machine (101), comprising the following steps: providing a core (2) for the active part (1) and shaped conductors (6) which are inserted into the core (2), joining in each case two of the end faces (9) to one another; and welding a respective pair (10) of the end faces (9) by means of a laser beam which is guided along a pattern having a trajectory (15).

Method for producing an active part (1) for a rotating electric machine (101), comprising the following steps: providing a core (2) for the active part (1) and shaped conductors (6) which are inserted into the core (2), joining in each case two of the end faces (9) to one another; and welding a respective pair (10) of the end faces (9) by means of a laser beam which is guided along a pattern having a trajectory (15).

A finned tube having a tube main body, on the outside of which, in particular separate or integral, fins are arranged, preferably circumferentially, wherein the fins and/or the tube main body are of a multi-layer material.

A method for monitoring a laser welding process for welding two workpieces using a laser wavelength, in which a pulsed laser beam is directed into the workpieces so as to melt a melting volume in a region of an interface of the two workpieces in order to produce a weld seam, and in which an intensity of a process radiation emitted by the melting volume is detected. According to the method for monitoring the lase welding process, in a first step, a detected intensity profile is evaluated with regard to at least one of the following features: (i) a depth of an intensity decrease, (ii) a duration of an intensity decrease, and (iii) a renewed increase in intensity after an intensity decrease. In a second step it is determined whether or not a gap between the two workpieces was bridged during the laser welding process based on the evaluation.

A method for monitoring a laser welding process for welding two workpieces using a laser wavelength, in which a pulsed laser beam is directed into the workpieces so as to melt a melting volume in a region of an interface of the two workpieces in order to produce a weld seam, and in which an intensity of a process radiation emitted by the melting volume is detected. According to the method for monitoring the lase welding process, in a first step, a detected intensity profile is evaluated with regard to at least one of the following features: (i) a depth of an intensity decrease, (ii) a duration of an intensity decrease, and (iii) a renewed increase in intensity after an intensity decrease. In a second step it is determined whether or not a gap between the two workpieces was bridged during the laser welding process based on the evaluation.

A button-type secondary battery includes an electrode assembly in which electrodes and separators are alternately layered; a can case having an internal accommodation space in which the electrode assembly is accommodated; and an electrode tab having one side connected to each of the electrodes of the electrode assembly and the other side welded to the can case. A welding pattern appearing at a welding part, at which the electrode tab is welded to the can case, includes a circular shape and an additional shape in addition to the circular shape.