Battery system optimization for eVTOL aircraft

An electrical system configured to provide propulsive power to a rotor system of an eVTOL aircraft having a takeoff and landing power mode and a cruise power mode, the electrical system comprising:

• a power battery system including a plurality of power cells and a power battery management system including a power battery DC-to-DC converter, the power cells having a power battery voltage;
• an energy battery system including a plurality of energy cells and an energy battery system including an energy battery DC-to-DC converter, the energy cells having an energy battery voltage, the energy battery management system in communication with the power battery management system;
• at least one electric motor configured to drive the rotor system, the electric motor having an operating voltage;
• and
• a distribution system electrically coupling the power battery system and the energy battery system to the at least one electric motor, the distribution system having a distribution voltage;
• wherein, the power battery system is connected in parallel to the energy battery system;
• wherein, in the takeoff and landing power mode, the energy battery DC-to-DC converter is configured to upconvert the energy battery voltage to the distribution voltage and the power battery DC-to-DC converter is configured to upconvert the power battery voltage to the distribution voltage so that both the power battery system and the energy battery system provide electrical power to the at least one electric motor;
• and
• wherein, in the cruise power mode, the energy battery DC-to-DC converter is configured to upconvert the energy battery voltage to the distribution voltage and the power battery DC-to-DC converter is configured to downconvert the distribution voltage to the power battery voltage so that the energy battery system provides electrical power to the at least one electric motor and to the power battery system to recharge the power cells.