Electric vehicle charging system

1. A charging system of an electric vehicle, comprising:

a drive battery which stores electric power for driving a motor of the electric vehicle;

an auxiliary battery which supplies electric power to the heater;

a charge amount detector which detects a charge amount of the auxiliary battery;

a heater which heats the drive battery;

an electric power supply device which converts electric power supplied from outside the electric vehicle and supplies the electric power to at least one of the drive battery and the heater;

a contactor which activates or deactivates a connection between the drive battery and the electric power supply device;

a temperature detector which detects a temperature of the drive battery; and

a controller which controls the contactor and the heater based on the temperature detected by the temperature detector,

wherein the controller

controls the contactor so as to deactivate the connection and conducts electricity to the heater when the temperature of the drive battery is less than a first predetermined temperature, and

controls the contactor so as to activate the connection when the temperature of the drive battery is the first predetermined temperature or greater, and

wherein the electric power supply device includes:

a charger which converts the electric power supplied from outside the electric vehicle and supplies the converted electric power to the drive battery; and

a voltage convertor which is connected to the charger, which converts voltage of the electric power converted by the charger, and which supplies the voltage to the auxiliary battery,

wherein the heater includes a plurality of heaters which can be activated or deactivated individually, or includes a variable resistance heater, so as to change heater output; and

the controller changes heater output power according to the charge amount of the auxiliary battery.

2. The electric vehicle charging system of claim 1 , wherein:

the controller increases the heater output as the charge amount of the auxiliary battery increases.

3. The electric vehicle charging system of claim 1 , further comprising:

an electrical component supplied with electric power from the auxiliary battery,

wherein the controller determines operation or non-operation of the electrical component according to the charge amount of the auxiliary battery.

4. The electric vehicle charging system of claim 3 ,

wherein the controller allows operation of the electrical component when the charge amount of the auxiliary battery is a predetermined charge amount or greater, and prohibits operation of the electrical component when the charge amount of the auxiliary battery is lower than the predetermined charge amount.

5. The electric vehicle charging system of claim 3 ,

wherein the controller determines whether to conduct or stop electricity to the heater, and also determines operation or non-operation of the electrical component, according to the temperature of the drive battery.

6. The electric vehicle charging system of claim 5 ,

wherein the controller

conducts electricity to the heater and prohibits operation of the electrical component when the temperature of the drive battery is lower than a first predetermined temperature,

conducts electricity to the heater and allows operation of the electrical component when the temperature of the drive battery is the first predetermined temperature or greater and lower than a second predetermined temperature which is higher than the first predetermined temperature, and

stops the heater and allows operation of the electrical component when the temperature of the drive battery is the second predetermined temperature or greater.