World-first Compact 7 Speed Automatic transmission for evs

Transmission‘Should-be-used’in EV
Design & Connecting
Transmission ‘Should-be-used’ in EV
Development Purpose
Despite strong buying incentives of EV with eco-friendly and lower maintenance costs,
higher price is the main burden for market.

Battery, BMS and related parts takes account for 50% of total manufacturing costs.
        Inverter and motor with complicated cooling system

The greatest advantage of Bygen’s C7SAT(Compact 7 Speed Automatic Transmission)
is to cut the production cost of EVs to compete with ICEs.
Power vs. performances in EVs
• While the electric motor is superior to internal combustion engine in terms of torque-rpm characteristics, all performances (top speed, gradeability and high speed acceleration) of single-speed EV except initial acceleration are inferior to ICE, even though they use two times higher output motor than output of ICE.

Temperature of the motor in single speed EV should be elevated along with increasing speed, especially in the field weakening regime. Half of electric energy wastes as heats, not being converted into kinetic energy. Higher temperature negatively effects on the motor efficiency.

Limitation of EV Cost-Cut
• Li-ion battery price is traded in limited range, which is not expected to drop sufficiently to give enough competitiveness to EV OEM.
• Current EV powertrain technology including inverter meets its limits to increase driving range of electric vehicles.
Multi-transmission to be adopted
• Because battery price decline is being slow and driving efficiency is limited from powertrain technology developments, multi-transmission for EVs is emerging as the best solutions for increasing driving range and saving the costs.

• Porsche introduced two-speed auto transmission for newly announcing Taycan, and Ford adopted 6-speed manual transmission for its testing electric Mustang. Many papers and researches say that multi-speed transmission should increase driving range of the electric vehicles as well as other performances.