Battery charging control method and system

A control unit for an electric or hybrid vehicle, the control unit comprising:

• a processor;
• and
• a memory coupled to the processor, the memory storing a program to be executed by the processor, the program including instructions for:
• receiving destination information;
• turning on a switch to charge a battery when the vehicle starts;
• turning off the switch for a first time interval when a State Of Charge (SOC) of the battery is larger than a preconfigured value, the first time interval derived based on an estimated destination arrival time derived from the destination information;
• and
• turning on the switch again at a time point at which the first time interval has passed, the switch being turned on again to charge the battery for a second time interval;
• wherein the first time interval decreases as a discharging power increases;
• wherein the discharging power corresponds to power loss for a predetermined time after the switch is turned off and an output power of a DC-DC converter is maintained;
• wherein the power loss is measured through a sensor connected to the battery;
• and
• wherein the discharging power is derived through an average value measured for the predetermined time from a time point at which the switch is turned off.

A system comprising:

• a battery;
• a DC-DC converter configured to convert a voltage level to charge the battery;
• a switch connected between the DC-DC converter and the battery;
• a navigation device configured to receive a destination from a user so as to derive an estimated destination arrival time;
• and
• a control unit, configured to:
• turn on the switch to charge the battery when a vehicle is on;
• when a State Of Charge (SOC) of the battery is larger than a preconfigured value, turn off the switch for a first time interval derived on the basis of an estimated destination arrival time transmitted from the navigation device;
• and
• turn on the switch again at a time point at which the first time interval has passed, so as to charge the battery for a second time interval;
• wherein the estimated destination arrival time is a time duration from a time point of turning off the switch to a time point of arrival;
• and
• wherein the first time interval is derived with an equation
• first time interval=T*(Pchg−2Pdiff−Pload)/(Pchg−Pdiff−Pload),
• where T indicates the estimated destination arrival time, Pchg indicates a charging power, Pdiff indicates a discharging power, and Pload indicates a load power.