A laser welding method is usable to weld a material containing copper as a main component. The laser welding method includes heating the material by irradiation with a first laser light and welding the material by irradiation of a portion, which has been irradiated with the first laser light, of the material with a second laser light with which an energy absorption rate of the copper contained in the material increases by an increase in a temperature of the material. A wavelength of the first laser light is 400 nm to 470 nm.

A laser welding method is usable to weld a material containing copper as a main component. The laser welding method includes heating the material by irradiation with a first laser light and welding the material by irradiation of a portion, which has been irradiated with the first laser light, of the material with a second laser light with which an energy absorption rate of the copper contained in the material increases by an increase in a temperature of the material. A wavelength of the first laser light is 400 nm to 470 nm.

A joining method includes: an overlapping step of overlapping a front surface of a first metal member with a back surface of a second metal member; and a welding step of welding the first metal member with the second metal member by hybrid welding, using a hybrid welding machine including a leading laser welding unit and a trailing arc welding unit. In the welding step, laser welding, by irradiating with a laser beam, and arc welding are performed from a front surface of the second metal member, along a preset travel route which is set on an overlapped part formed by the first metal member and the second metal member overlapped with each other, to the overlapped part, and the laser beam is oscillated to cross the preset travel route.

A joining method includes: an overlapping step of overlapping a front surface of a first metal member with a back surface of a second metal member; and a welding step of welding the first metal member with the second metal member by hybrid welding, with use of a hybrid welding machine including a leading laser welding unit and a trailing arc welding unit. In the welding step, laser welding, by irradiating a laser beam, and arc welding are performed, along a preset travel route set on an inner corner portion formed by the front surface of the first metal member and an end surface of the second metal member, to the inner corner portion and the laser beam is oscillated to cross the preset travel route.

A method of laser welding a workpiece stack-up that includes at least two overlapping metal workpieces is disclosed. The method includes advancing a beam spot of a laser beam relative to a top surface of the workpiece stack-up and along a beam travel pattern to form a laser weld joint, which is comprised of resolodified composite metal workpiece material, that fusion welds the metal workpieces together. And, while the beam spot is being advanced along the beam travel pattern, between a first point and a second point, which may or may not encompass the entire beam travel pattern, at least one of the following laser beam parameters is repeatedly varied: (1) the power level of the laser beam; (2) the travel speed of the laser beam; or (3) the focal position of the laser beam relative to the top surface of the workpiece stack-up.

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.

The invention relates to a method for producing a bipolar plate (5), comprising the following steps: a. providing two planar components (7), which are present in particular in a stacked manner, b. integrally bonding the two planar components (7), in particular by welding, in a joining plane (34), wherein, prior to integrally bonding, internal stresses (9) are introduced into at least one of the two planar components (7). The invention also relates to a fuel cell (1) comprising a bipolar plate (5) produced according to this method.

The invention relates to a method for producing a bipolar plate (5), comprising the following steps: a. providing two planar components (7), which are present in particular in a stacked manner, b. integrally bonding the two planar components (7), in particular by welding, in a joining plane (34), wherein, prior to integrally bonding, internal stresses (9) are introduced into at least one of the two planar components (7). The invention also relates to a fuel cell (1) comprising a bipolar plate (5) produced according to this method.

A method for laser welding two coated workpieces includes positioning an upper workpiece and a lower workpiece on top of each other and passing a first laser beam over the upper and lower workpieces from a side of the upper workpiece so as to at least partially evaporate the respective coating of each of the workpieces on their facing sides along a depletion trace. A second laser beam is passed over the workpieces from the side of the upper workpiece so as to melt a material of the two workpieces within the depletion trace, and thereby weld the workpieces to one another. In the first laser passing, the first laser beam melts the material of the upper workpiece, so that a web of non-melted material of the upper workpiece remaining between the melted material of the upper workpiece and the facing side of the upper workpiece.

A method for laser welding two coated workpieces includes positioning an upper workpiece and a lower workpiece on top of each other and passing a first laser beam over the upper and lower workpieces from a side of the upper workpiece so as to at least partially evaporate the respective coating of each of the workpieces on their facing sides along a depletion trace. A second laser beam is passed over the workpieces from the side of the upper workpiece so as to melt a material of the two workpieces within the depletion trace, and thereby weld the workpieces to one another. In the first laser passing, the first laser beam melts the material of the upper workpiece, so that a web of non-melted material of the upper workpiece remaining between the melted material of the upper workpiece and the facing side of the upper workpiece.