If the battery pack is the heart of an electric vehicle, then the bus bar is the aorta, conducting electrical current to the motors and other systems. For light weight and good conduction of heat and electricity, bus bars are made of copper, aluminum or a combination of the two.
Joining these dissimilar materials has posed a challenge. Soldered butt joints are one option, but defects can result from various metallurgic alterations produced during fabrication. Laser welded lap joints are another option, but it’s expensive.