Communication method between master controller and slave controller, slave controller for the same, and battery management system using the same
Disclosed are a communication method between a master controller and slave controllers, a slave controller for the communication method, and a battery management system using the communication method and the slave controller, in which the master controller receives safety information about battery cells through a plurality of channels even when each of a plurality of slave controllers includes only one micro controller unit, thereby minimizing the increase in the cost and enhancing the safety of the battery management system. The communication method includes performing bidirectional communication between a master controller and first to N th (where N is an integer equal to or more than two) slave controllers through a first communication channel, and receiving, by the master controller, an indication signal through a second communication signal via the first to N th slave controllers.
1. A slave controller comprising:
a first voltage sensing unit and a second voltage sensing unit connected to both ends of a battery cell to sense a voltage of the battery cell; and
a micro controller unit (MCU) configured to convert a first sensing voltage from the first voltage sensing unit into voltage information data which is digital data, output the voltage information data to a first communication channel, determine whether the battery cell is overcharging or over-discharging based on a second sensing voltage from the second voltage sensing unit, and output an indication signal to a second communication channel,
wherein when the slave controller is a first slave controller connected to a transmission terminal of a master controller through the second communication channel, the first slave controller is configured to receive a first indication signal from the master controller through the second communication channel, transmit a second indication signal differing from the first indication signal to a second slave controller through the second communication channel when it is determined that the battery cell is abnormal, and transmit the first indication signal to the second slave controller when it is determined that the battery cell is normal,
wherein when the slave controller is an N th slave controller connected to a reception transmission terminal of the master controller through the second communication channel and receives the first indication signal from N−1 th slave controller, the N th slave controller is configured to transmit the second indication signal to the master controller through the second communication channel when it is determined that the battery cell is abnormal, and transmit the first indication signal to the master controller when it is determined that the battery cell is normal, and
wherein when the slave controller is an N th slave controller and receives the second indication signal from an N−1 th slave controller, the N th slave controller is configured to transmit the second indication signal to the master controller through the second communication channel.
2. The slave controller of claim 1 , wherein;
the MCU comprises a comparator;
when the second sensing voltage is between a first voltage threshold value and a second voltage threshold value, the MCU is configured to output a first comparison signal; and
when the second sensing voltage is equal to or greater than the first voltage threshold value or is equal to or less than the second voltage threshold value, the MCU is configured to output a second comparison signal.
3. The slave controller of claim 2 , wherein the MCU is configured to convert a sensing temperature of the battery cell into temperature information data which is digital data, output the temperature information data to the first communication channel, determine whether the battery cell is overheating based on the sensing temperature, and output the indication signal to the second communication channel.
4. The slave controller of claim 3 , wherein,
when the sensing temperature is between a first temperature threshold value and a second temperature threshold value, the comparator outputs the first comparison signal, and
when the sensing temperature is equal to or greater than the first temperature threshold value or is equal to or less than the second temperature threshold value, the comparator outputs the second comparison signal.
5. The slave controller of claim 4 , wherein,
when the first indication signal is input through the second communication channel and the first comparison signal is input from the comparator, the MCU is configured to output the first indication signal to the second communication channel,
when the first indication signal is input through the second communication channel and the second comparison signal is input from the comparator, the MCU is configured to output the second indication signal to the second communication channel, and
when the second indication signal is input through the second communication channel, the MCU is configured to output the second indication signal to the second communication channel.
6. The slave controller of claim 3 , wherein the MCU comprises:
an analog-to-digital converter (ADC) configured to convert the first sensing voltage into the voltage information data, which is digital data, and convert the sensing temperature into the temperature information data which is digital data;
a communication module configured to convert each of the voltage information data and the temperature information data into a communication packet suitable for the first communication channel to transmit the communication packet; and
a central processing unit (CPU) configured to output the voltage information data and the temperature information data, received from the ADC, to the communication module.
7. The slave controller of claim 6 , wherein
the first voltage sensing unit transmits the first sensing voltage in a differential signal form by using a plurality of signal lines to the ADC, and
the second voltage sensing unit transmits the second sensing voltage to the comparator by using one signal line.