My understanding is since the specifications are given by the motor it shall be that of the phase currents that the windings can handle, since it is rated current it will be the RMS value of the phase current.
"RATED CURRENT" for a motor is usually understood to the current from an external source connected to the motor's power input connection, usually with the motor delivering the rated torque or the rated power (horsepower), or Watts.
DISHONEST advertisers may claim the peak power that a motor can deliver for a short time, often for one revolution.
Revisit post #5, please. "Rated current" IS the input current to the motor. So if that is the only load on the battery, it would equal the battery current. The various current levels inside a motor are seldom available for convenient measurement in a user application.
"Rated Current" is the value presented to the user that the motor will require to be supplied for the full rated output power.
The practical value of a motor current rating is to inform as to what will be required to power that motor to deliver it's rated power. The required power from the motor is determined by the specific application. THAT determination can be quite tedious. Lots of math and quite a few measurements.