Battery balancing apparatus and battery balancing method

1. A battery balancing apparatus, comprising:

a plurality of balancing circuits, wherein each balancing circuit is connected in parallel to a respective battery cell among a plurality of battery cells and the plurality of balancing circuits are connected in series to each other, in one-to-one relationship; and

a control unit operably coupled to each balancing circuit,

wherein the control unit is configured to select at least one of the plurality of battery cells as a balancing target, based on a SOC of each battery cell, and output an enable signal and a balancing message to each balancing circuit connected to each battery cell selected as the balancing target,

wherein each balancing circuit is configured to transmit a first wireless signal and a second wireless signal corresponding to the balancing message by using electric energy stored in each battery cell, when the enable signal is received by each balancing circuit, and

wherein the first wireless signal and the second wireless signal are at least partially canceled out by each other.

2. The battery balancing apparatus according to claim 1 ,

wherein each balancing circuit includes:

a balancing switch configured to operate in an ON state in response to the enable signal; and

a first wireless transmitter and a second wireless transmitter connected to the balancing switch in series,

wherein the first wireless transmitter is configured to transmit the first wireless signal while the balancing switch is operating in the ON state, and

wherein the second wireless transmitter is configured to transmit the second wireless signal while the balancing switch is operating in the ON state.

3. The battery balancing apparatus according to claim 1 ,

wherein a phase of the first wireless signal and a phase of the second wireless signal are opposite to each other.

4. The battery balancing apparatus according to claim 3 ,

wherein the first wireless signal and the second wireless signal are unmodulated sine waves having the same frequency and amplitude.

5. A battery balancing apparatus, comprising:

a plurality of balancing circuits, wherein each balancing circuit is connected in parallel to a respective battery cell among a plurality of battery cells and the plurality of balancing circuits are connected in series to each other, in one-to-one relationship; and

a control unit operably coupled to each balancing circuit,

wherein the control unit selects at least two of the plurality of battery cells as balancing targets, based on a SOC of each battery cell,

wherein when a first battery cell and a second battery cell are selected from the plurality of battery cells as the balancing targets, the control unit is configured to transmit an enable signal and a first balancing message to a first balancing circuit among the plurality of balancing circuits connected in parallel to the first battery cell and transmit the enable signal and a second balancing message to a second balancing circuit among the plurality of balancing circuits connected in parallel to the second battery cell,

wherein the first balancing circuit is configured to transmit a first wireless signal corresponding to the first balancing message by using electric energy stored in the first battery cell when the enable signal is received by the first balancing circuit,

wherein the second balancing circuit is configured to transmit a second wireless signal corresponding to the second balancing message by using electric energy stored in the second battery cell when the enable signal is received by the second balancing circuit, and

wherein the first wireless signal and the second wireless signal are at least partially canceled out by each other.

6. The battery balancing apparatus according to claim 5 ,

wherein each balancing circuit includes:

a balancing switch configured to operate in an ON state in response to the enable signal; and

a first wireless transmitter connected to the balancing switch in series,

wherein the first wireless transmitter is configured to transmit a wireless signal corresponding to a balancing message output from the control unit, while the respective balancing switch is operating in the ON state.

7. The battery balancing apparatus according to claim 5 ,

wherein a phase of the first wireless signal and a phase of the second wireless signal are opposite to each other.

8. The battery balancing apparatus according to claim 7 ,

wherein the first wireless signal and the second wireless signal have the same frequency, and

wherein the first wireless signal and the second wireless signal have the same amplitude.

9. The battery balancing apparatus according to claim 5 ,

wherein each balancing circuit further includes a second wireless transmitter connected to the respective balancing switch in series,

wherein the control unit is configured to transmit the enable signal and a third balancing message to the second balancing circuit when a SOC of the second battery cell is greater than a SOC of the first battery cell, and

wherein the second wireless transmitter of the second balancing circuit is configured to transmit a third wireless signal corresponding to the third balancing message by using electric energy stored in the second battery cell.

10. The battery balancing apparatus according to claim 9 ,

wherein the first wireless signal, the second wireless signal and the third wireless signal have the same frequency,

wherein a phase of the second wireless signal is opposite to a phase of the first wireless signal and a phase of the third wireless signal, and

wherein an amplitude of the second wireless signal is equal to the sum of an amplitude of the first wireless signal and an amplitude of the third wireless signal.

11. A battery pack, comprising the battery balancing apparatus according to claim 1 .

12. A battery balancing method, comprising:

by a control unit, selecting at least one of a plurality of battery cells as a balancing target, based on SOCs of the plurality of battery cells connected in series to each other;

by the control unit, outputting an enable signal and a balancing message to each balancing circuit connected in parallel to each battery cell selected as the balancing target; and

by each balancing circuit, transmitting a first wireless signal and a second wireless signal corresponding to the balancing message by using electric energy stored in each battery cell selected as the balancing target, when the enable signal is received by each balancing circuit,

wherein the first wireless signal and the second wireless signal are at least partially canceled out by each other.

13. The battery balancing method according to claim 12 ,

wherein a phase of the first wireless signal and a phase of the second wireless signal are opposite to each other.

14. A battery pack, comprising the battery balancing apparatus according to claim 5 .