Battery pack voltage-switching systems and control logic for multi-pack electric-drive motor vehicles

An electric-drive motor vehicle comprising:

• a vehicle body with multiple road wheels attached to the vehicle body;
• a traction motor attached to the vehicle body and operable to drive one or more of the road wheels to thereby propel the motor vehicle;
• a battery system with first and second traction battery packs attached to the vehicle body and operable to power the traction motor;
• and
• a vehicle controller communicatively connected to the traction motor and the traction battery packs, the vehicle controller being programmed to:
• receive a voltage switch signal to change a battery system output voltage of the battery system from a first voltage to a second voltage;
• determine if a machine speed of the traction motor is less than a calibrated base machine speed;
• responsive to the machine speed being less than the calibrated base machine speed, transmit a pack isolation signal to a power inverter to open multiple inverter switches thereby electrically disconnecting the first and second traction battery packs from the traction motor;
• determine if a bus current of a direct current (DC) bus electrically connecting the first and second traction battery packs to the power inverter is less than a calibrated bus current threshold;
• and
• responsive to the bus current being less than the calibrated bus current threshold, transmit to a set of pack contactor switches an open signal to open one of the pack contactor switches and a close signal to close another of the pack contactor switches thereby causing the first and/or second traction battery packs to output the second voltage.