Electric motors rev much higher than gas engines and inherently make maximum torque from zero rpm up to a fixed point. This enables them to reach top speed in a single gear. In contrast, combustion engines make their power at higher rpm and need multiple gear ratios to both reach higher speeds and avoid over-revving the engine.
An electric vehicle’s transmission is much simpler than an ICE vehicle’s multi-speed transmission. An EV transmission has a more compact shape and fewer moving parts, and it’s likely to be more reliable and easier to maintain. An EV transmission can accelerate more quickly, quietly and smoothly than a non-EV transmission since it is neither shifting gears nor revving a loud gas engine.
Every vehicle, whether electric or ICE, experiences varying levels of drivetrain loss. This is the vehicle’s inability to use all the energy that’s produced by burning fuel or that’s stored in the battery due to heat generation, friction in the transmission and drag forces. According to the U.S. Department of Energy, an EV’s drive system is responsible for a 15% to 20% energy loss, compared to a 64% to 75% loss for a gasoline engine. This makes the EV significantly more energy-efficient than its gas counterpart.
Modern automatic transmissions on gas cars have anywhere between six and 10 speeds. There are numerous types, including a traditional torque converter automatic transmission, continuously variable transmission, dual-clutch transmission and manual transmission. All of these are more complicated, larger and potentially more expensive to produce and repair than a simpler electric car transmission.