A Study on Electrical and Electrochemical Characteristics of Friction Stir Welded Lithium-Ion Battery Tabs for Electric Vehicles

This study attempts to join copper (Cu) and aluminium (Al) sheets in micro-thickness by using friction stir welding. These materials are being used as current collectors in lithium-ion (li-ion) battery which are employed as power sources for electric vehicles. Several experiments have been carried out, followed by the measurement of electrical conductivity by using a 4-probe setup and electrochemical analysis by using a potentiodynamic polarization test and an electro impedance spectroscopy test in lithium phosphorus hexafluoride (LiPF6), an electrolytic medium. The welded samples have been found to achieve an electrical conductivity of 9% less than the base Cu and the corrosion resistance of the welded samples has been found to be increasing because of the formation of inter-metallic compounds such as Al4Cu9, AlCu4 and AlCu at the weld interface. Among them AlCu4 has the highest hardness and the recovery elastic modulus than the rest.