Battery charging system and battery charging method for electrically driven vehicle

A battery charging system for an electrically driven vehicle, the battery charging system comprising:

• a charging connector to which a charging plug of an external power supply is connected;
• a charging controller configured to control external charging for charging a battery with the external power supply;
• an external charging timer configured such that an external charging start time is able to be set by a user's operation;
• a temperature acquirer configured to acquire a battery temperature;
• and
• a heater configured to increase the battery temperature,
• wherein, in a case where the external charging start time is set in the external charging timer when the charging plug is inserted into the charging connector, the charging controller is configured to perform standby setting of the external charging before the external charging start time and transit to a pause state,
• the charging controller is configured to be intermittently activated during a timer charging setting period from a pause period start time at which transition is made to the pause state to the external charging start time, and when the battery temperature at a time of activation of the charging controller is equal to or lower than a predetermined temperature, execute a temperature increase mode in which the heater is operated to increase the battery temperature, and
• when the temperature increase mode is executed, the charging controller is configured to release the standby setting of the external charging and execute a temperature increase charging mode in which the external charging is performed.