A method of analyzing a welded connection during laser welding of workpieces includes acquiring a first measurement signal for a process radiation generated during laser welding, acquiring a second measurement signal for a laser radiation reflected by the workpieces, determining whether there is a gap between the workpieces based on the first measurement signal, and when it is determined that there is a gap, determining based on the second measurement signal whether there is a welded connection.

A metal foil welding method includes: a first step of stacking a plurality of metal foils; and a second step of welding the plurality of stacked metal foils by irradiating the plurality of metal foils with laser light having a wavelength of 400 nm or more and 500 nm or less.

A metal foil welding method includes: a first step of stacking a plurality of metal foils; and a second step of welding the plurality of stacked metal foils by irradiating the plurality of metal foils with laser light having a wavelength of 400 nm or more and 500 nm or less.

A rechargeable battery pack unit encompassing a rechargeable battery cell, which includes a cell pole, and encompassing a current collector, the cell pole being integrally joined to the current collector in a connecting area, a ratio of a wall thickness of the cell pole and the thickness of the current collector being maximally, and the current collector being made of copper.

A rechargeable battery pack unit encompassing a rechargeable battery cell, which includes a cell pole, and encompassing a current collector, the cell pole being integrally joined to the current collector in a connecting area, a ratio of a wall thickness of the cell pole and the thickness of the current collector being maximally, and the current collector being made of copper.

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.

The present invention includes a laser-welded lap joint including a weld zone formed by laser lap welding in a lapped portion including a plurality of lapped steel sheets. The weld zone includes a main weld zone that penetrates the steel sheets in the lapped portion and a final weld zone formed at one end of the main weld zone and having a crater, and the weld zone satisfies formulas (1) to (4):
L≥15.0;  (1)
10.0≥L2≥2l.sub.c;  (2)
t1≥2d.sub.c;  (3)
w.sub.c>d.sub.c  (4).

The present invention includes a laser-welded lap joint including a weld zone formed by laser lap welding in a lapped portion including a plurality of lapped steel sheets. The weld zone includes a main weld zone that penetrates the steel sheets in the lapped portion and a final weld zone formed at one end of the main weld zone and having a crater, and the weld zone satisfies formulas (1) to (4):
L≥15.0;  (1)
10.0≥L2≥2l.sub.c;  (2)
t1≥2d.sub.c;  (3)
w.sub.c>d.sub.c  (4).

A welded steel part obtained by welding a first sheet with a second sheet, at least one with a coating of aluminum alloy. The welding uses a welding wire which, after melting and cooling, constitutes a weld bead connecting the first sheet to the second sheet and being part of said welded steel part. The respective peripheral edge of the first and second sheets are in a joggled edge type configuration in which the peripheral edge of the first sheet is arranged above, and on or near the upper face of an end portion of the peripheral edge of the second sheet which is extended by an inclined junction portion, at least one part of the upper face of the inclined junction portion delimits at least laterally with the edge of the peripheral edge of the first sheet a groove receiving the weld bead, the inclined joining portion extending by a welding portion in longitudinal continuity with the peripheral edge of the first sheet.