Power control system and method

A power control method for controlling power to an electronic device, comprising:

• setting a protection voltage of a power storage unit;
• discharging the power storage unit with a discharge voltage and a discharge current value at a discharge temperature, wherein the power storage unit stops discharging when the discharge voltage is smaller than the protection voltage;
• determining whether the discharge temperature is lower than a predetermined temperature;
• determining whether the discharge current value is larger than a particular current value when the discharge temperature is lower than the predetermined temperature, wherein the particular current value is selected from a plurality of predetermined current values according to the discharge temperature;
• and
• changing the protection voltage when the discharge current value is larger than the particular current value.