The multi-speed gearbox is currently a research trend aimed at replacing the traditional reduction gears in electric vehicles. The flexibility in selecting appropriate gear ratios helps electric vehicles manoeuvre effortlessly under different operating conditions. In addition to increasing the torque of the transmission system, a multi-speed gearbox enables the electric motor to work at its maximum in the high-efficiency region, thereby saving overall vehicle energy. Nonetheless, a significant drawback of the multi-speed gearbox is the phenomenon of torque interruption during gear-shifting, causing jerking or requiring energy expenditure to compensate for the torque. This issue needs to be studied even more when the gear ratio values of the gearbox have a large discrepancy. Consequently, in this work, we will continue to develop a novel gear-shifting mechanism using non-circular gears to reduce the phenomenon of torque interruption. The gear-shifting phase will consider motor operating parameters and battery discharge current. Finally, the research results are simulated using Matlab/Simulink. The research results have important implications for developing multi-speed gearboxes and increasing the battery life of electric vehicles.