Battery pack with temperature sensing unit

1. A battery pack, comprising:

a battery including at least one battery cell connected between a pair of external terminals, the pair of external terminals connected to an engine starter for starting an engine;

a sensor to detect a temperature of the battery and a current of the battery;

a controller to:

detect an engine-start attempt to start the engine using the engine starter based on the temperature of the battery,

compare the temperature of the battery with a reference temperature value after detecting the engine-start attempt, and

output a self-discharge signal when the temperature of the battery is lower than the reference temperature value; and

a self-discharge circuit connected between the pair of external terminals in parallel with the battery, the self-discharge circuit to self-discharge the battery based on the self-discharge signal to increase the temperature of the battery, wherein

the sensor is to detect a voltage of the battery, and

the controller is to determine that the engine-start attempt was made but failed when the voltage of the battery become lower than a reference voltage value at a time when the current of the battery exceeds a reference current value.

2. The battery pack as claimed in claim 1 , wherein the controller is to:

determine that the engine-start attempt was made based on the current of the battery in excess of the reference current value;

determine that the engine-start attempt was failed when the voltage of the battery becomes lower than the reference voltage value at the time when the current of the battery exceeds the reference current value;

determine that the engine-start attempt was completed when the current of the battery becomes lower than the reference current value;

compare the temperature of the battery with the reference temperature value after determining that the engine-start attempt was made but failed; and

output the self-discharge signal to the self-discharge circuit to self-discharge the battery using the self-discharge circuit when the temperature of the battery is lower than the reference temperature value.

3. The battery pack as claimed in claim 1 , wherein:

the sensor is to detect a voltage of the battery, and

the controller is to:

determine that the engine-start attempt was made when the current of the battery becomes higher than a reference current value and then falls below the reference current value;

determine whether the engine-start attempt has succeeded by comparing a first voltage of the battery measured before the current of the battery becomes higher than the reference current value with a second voltage of the battery measured after the current of the battery becomes lower than the reference current value;

determine that the engine-start attempt has failed when the second voltage is lower than the first voltage;

compare the temperature of the battery with the reference temperature value after determining that the engine-start attempt was made but failed; and

output the self-discharge signal to the self-discharge circuit to self-discharge the battery using the self-discharge circuit when the temperature of the battery is lower than the reference temperature value.

4. The battery pack as claimed in claim 1 , wherein the controller is to:

monitor the temperature of the battery while outputting the self-discharge signal, and

stop outputting the self-discharge signal when the temperature of the battery becomes equal to or higher than the reference temperature value.

5. The battery pack as claimed in claim 1 , wherein the controller is to output the self-discharge signal and stop outputting the self-discharge signal after a predetermined time period based on an initial temperature of the battery compared with the reference temperature value.

6. The battery pack as claimed in claim 5 , wherein:

the battery is self-discharged to generate heat during the predetermined time period, and

the heat to be generated in a sufficient amount that the temperature of the battery is equal to or higher than the temperature reference value after the predetermined time period.

7. The battery pack as claimed in claim 5 , wherein the controller is to store information indicative of the predetermined time period during which the self-discharge signal is output based on the initial temperature of the battery.

8. The battery pack as claimed in claim 1 , wherein the self-discharge circuit includes a self-discharge switch to connect the pair of external terminals with each other based on the self-discharge signal.

9. The battery pack as claimed in claim 1 , wherein:

the self-discharge circuit includes a self-discharge switch and a self-discharge resistor that are connected in series between the pair of external terminals, and

the self-discharge switch is to be turned on or off based on the self-discharge signal.

10. A vehicle comprising the battery pack of as claimed in claim 1 .

11. The battery pack as claimed in claim 1 , wherein

the controller is to determine that the engine-start attempt was made when the current of the battery becomes higher than a reference current value.