The electric vehicle market is driving the need for innovative joining processes that can be scaled up to meet the aggressive requirements of quality and productivity. In addition to these requirements the need to join a large number of foil stacks is evident to improve the efficiency of these vehicles.  Copper, aluminum and stainless steel are typically required to be joined in these applications.  These materials can have thicknesses from eight to several hundred microns creating a challenge to fixture and ensure binding between all layers. Conventional infra-red lasers have been used but they struggle to deal with the challenges of welding highly reflective material.

This paper explores an alternative approach of using blue wavelength lasers for the notoriously difficult welds. The change in wavelength dramatically improves absorption -   simplifying the process and providing defect and spatter free results whilst using the automation advantages of laser processing.  The stability of this process will show the possibility to increase layer thicknesses being joined limiting cutting of thin materials and creating more efficient batteries and packs.  Examples in battery cell, pack production and e-mobility applications will be presented along with the metallurgy of the samples and the process in which the samples underwent.