Investigations on laser beam welding of thin aluminum foils with additional filler wire

Abstract

Nowadays, battery-electric drives and energy storage are elected to be the future technologies. In the manufacturing of parts for electric applications, laser beam welding is an appropriate and favorable welding method. The characteristics of high welding speed, local heat input, and the contact-free process allow efficient and automatable processes. For electrodes, mainly copper and aluminum are used. Many foils with thicknesses of an area of 10 μm have to be connected to create battery cells. Different than expected, aluminum is a more challenging material to produce than others. Pore formation is also extended in aluminum due to the presence of air between the foils. The connecting cross section is thereby reduced. Furthermore, there is detachment in the fusion area and a high weld seam undercut. In addition to insufficient clamping, a lack of material reduces strength and, thus, usability. In the research presented here, the use of aluminum filler wire (AA 1050A) and shielding gas are investigated for the application of welding 40 aluminum foils (AA 1050A) with a thickness of 15 μm to an aluminum sheet with a thickness of 2 mm using infrared laser beam wavelength. The aims of the process development are welds with high connection widths and high quality as well as reproducibility to provide excellent mechanical properties and the highest electrical conductivity.