Battery charging system and method of controlling the same

A battery charging system, comprising:

• a battery for storing electric energy therein;
• a main switch unit connected, at one terminal thereof, to an output terminal of the battery, and turned on when the battery is charged;
• a charge switch unit connected to the other terminal of the main switch unit, and turned on when the battery is charged;
• a charging equipment connected to the other terminal of the charge switch unit, for charging the battery;
• a capacitor connected in parallel between the other terminal of the main switch unit and one terminal of the charge switch unit to form an electric potential during charging;
• a forced discharge unit connected in parallel between the other terminal of the main switch unit and the one terminal of the charge switch unit to discharge a voltage of the capacitor when a relay is turned on;
• a fusion determination unit connected in parallel between the other terminal of the charge switch unit and an output terminal of the charging equipment;
• and
• a controller configured to determine whether ignition of a vehicle is turned off or charging of the battery is completed, to determine whether the charge switch unit is fused based on a result of comparison between a discharge rate of the capacitor and a preset first reference value after the charge switch unit is turned on/off when the ignition is turned off, and to determine whether a high voltage remains at the output terminal of the charging equipment based on a result of comparison between the voltage of the capacitor and a preset second reference value after the charge switch unit is turned off when the charging is completed.

A method of controlling a battery charging system, comprising:

• providing the battery charging system, including:
• a battery configured to store electric energy therein;
• a charging equipment configured to provide electric power to the battery;
• a charge switch unit configured to determine an electrical connection between the battery and the charging equipment according to an ON/OFF operation thereof;
• a capacitor electrically connected in parallel between the battery and the charge switch unit to form an electric potential during charging;
• and
• a controller configured to determine whether an ignition of a vehicle is turned off or charging of the battery is completed, to determine whether the charge switch unit is fused based on a result of comparison between a discharge rate of the capacitor and a preset first reference value after the charge switch unit is turned on/off when the ignition is turned off, and to determine whether a high voltage remains at an output terminal of the charging equipment based on a result of comparison between a voltage of the capacitor and a preset second reference value after the charge switch unit is turned off when the charging is completed;
• determining whether the ignition of the vehicle is turned off or the charging of the battery is completed;
• determining whether the charge switch unit is fused based on the result of comparison between the discharge rate of the capacitor and the preset first reference value after the charge switch unit is turned on/off when the ignition is turned off;
• and
• determining whether the high voltage remains at the output terminal of the charging equipment based on the result of comparison between the voltage of the capacitor and the preset second reference value after the charge switch unit is turned off when the charging is completed.