Product Code: ICA11_M203

Prospects of Welding Foils with Solid State Laser for Lithium-Ion Batteries
Authors:
Renald Schedewy, Fraunhofer Institute for Material and Beam Technology (IWS); Dresden Germany
Eckhard Beyer, Fraunhofer Institute for Material and Beam Technology (IWS), University of Technology Dresden; Dresden Germany
Berndt Brenner, Fraunhofer Institute for Material and Beam Technology (IWS); Dresden Germany
Jens Standfuss, Fraunhofer Institute for Material and Beam Technology (IWS); Dresden Germany
Presented at ICALEO 2011

Lithium Ion batteries will become a key element in future E-mobility. In a layered pouch cell design the electrical contacts consists of conductive foil tapes that have to be welded to the terminal. Common used ultra-sonic welding technologies have some process-inherent restriction like risk for mechanical damaging of the 10...20µm thin Al or Cu foils, wear of the weld-ing-sonotrode and limited mechanical strength and electrical conductivity of the welding spot caused by the adhesive bonding interfaces.
For a high volume and high power applications for future E-mobility the laser beam welding technology with HQ solid state laser offers new possibilities. Be-side the easy LBW process automation a higher strength and a lower electrical resistance of the weld caused by a fully metallic bonding can be achieved. But laser beam welding of 10...20µm thin foil pack-ages are challenging with respect to the gap condition in overlap configuration, necessary new clamping con-cepts and welding strategies to minimize the heat in-put. In the paper weld joint geometries, influence of laser sources and beam defection techniques will be specifically analysed.