An emerging trend in automotive electrical distribution is the requirement for reliable and efficient copper-to-aluminum joining. Roll bonded Cu-Al clads offer benefits for wiring systems, providing like-metal joining and avoiding brittle intermetallic (IMC) phases created during welding of incompatible metals. High amperage pulse testing was used to test the IMC for resistance aging in roll clad DovetailTM Cu-Al busbars, demonstrating stability of the electrical performance after a total of 50,000 high current cycles. This is supported by 2D CFD modelling of the electrical current through the clad interface, providing current density distribution from Cu-to-Al and predicting resistive heat generation from the intermetallic layer to be <1% of the total resistive heating generated by the clad busbar. Minimal localized resistive losses and a distributed current density in the IMC suggest ohmic heating from the Cu and Al base metals are the predominant drivers of IMC growth. These results are used to predict 10 year IMC growth in aggressive use EV applications such as taxis or ride sharing, and find long term stability of clad Cu-Al busbars is expected in major US cities when ohmic heating of busbars is limited to <200˚C over ambient.