Power supply system for electric vehicle and method for controlling the same

A power supply system for an electric vehicle, comprising:

• a battery module having a negative electrode, a first positive electrode and a second positive electrode, wherein the first positive electrode is configured to output a first voltage, the second positive electrode is configured to output a second voltage, and the second voltage is greater than the first voltage;
• a first DC/DC converter having an input terminal connected with the second positive electrode;
• a second DC/DC converter having an input terminal connected with the second positive electrode;
• a first switch connected between the second positive electrode and the first DC/DC converter;
• a second switch connected between the second positive electrode and the second DC/DC converter;
• and
• a third switch connected between the first positive electrode and an output terminal of the second DC/DC converter;
• and a controller, connected with the first switch and the second switch respectively, and configured to switch on the second switch and switch off the first switch when the electric vehicle is started or running, and to switch off the second switch and switch on the first switch when the electric vehicle is stopped.