Apparatus and method for controlling connection of battery packs

1. An apparatus for controlling the connection of a plurality of battery packs, the apparatus comprising:

a switching unit provided on a charge/discharge path of each battery pack to selectively open and close the charge/discharge path;

a first control unit provided for each battery pack to determine the state of charge (SOC) of each battery pack and control the opening/closing of the switching unit; and

a second control unit to receive the determined SOC value of each battery pack from the first control unit, group battery packs having SOC values within a predetermined error range, select a group containing a largest number of battery packs, connect the battery packs of the selected group in parallel, charge or discharge the parallel-connected battery packs so that a difference in SOC between the parallel-connected battery packs and a non-connected battery pack falls within a predetermined range, and additionally connect the non-connected battery pack in parallel.

2. The apparatus according to claim 1 ,

wherein the second control unit charges the entire battery pack connected in parallel after connecting the plurality of battery packs.

3. The apparatus according to claim 1 ,

wherein the first control unit is implemented as a battery management system (BMS) of each battery pack.

4. The apparatus according to claim 1 ,

wherein the switching unit is implemented as a field effect transistor (FET), a relay, or an insulated gate bipolar transistor (IGBT).

5. An apparatus for controlling the connection of battery packs that controls connection of an additional battery pack to at least two parallel-connected battery packs, the apparatus comprising:

a switching unit provided on a charge/discharge path of each battery pack to selectively open and close the charge/discharge path;

a first control unit provided for each battery pack to determinea state of charge (SOC) of each battery pack and control the opening/closing of the switching unit; and

a second control unit to receive the determined SOC value of each battery pack from the first control unit, compare the SOCs of the parallel-connected battery packs and the additional battery pack, when a difference in SOC between the parallel-connected battery packs and the additional battery pack is out of a predetermined range, charge or discharge the parallel-connected battery packs so that the difference in SOC between the parallel-connected battery packs and the additional battery pack falls within the predetermined range, and connect the additional battery pack in parallel.

6. The apparatus according to claim 5 ,

wherein the second control unit charges the entire battery pack connected in parallel after connecting the additional battery pack in parallel.

7. The apparatus according to claim 5 ,

wherein the first control unit is implemented as a battery management system (BMS) of each battery pack.

8. The apparatus according to claim 5 ,

wherein the switching unit is implemented as a field effect transistor (FET), a relay, or an insulated gate bipolar transistor (IGBT).

9. A method for controlling the connection of a plurality of battery packs, the method comprising:

determining the state of charge (SOC) of each battery pack;

comparing the determined SOC values and grouping battery packs having SOC values within a predetermined error range;

selecting a group containing a largest number of battery packs and connecting the battery packs of the selected group in parallel;

charging or discharging the parallel-connected battery packs so that a difference in SOC between the parallel-connected battery packs and a non-connected battery pack falls within a predetermined range; and

additionally connecting the non-connected battery pack in parallel.

10. The method according to claim 9 , further comprising:

charging the entire battery pack connected in parallel after additionally connecting the battery pack in parallel.

11. The method according to claim 9 ,

wherein the SOC of each battery pack is determined by a battery management system (BMS) of each battery pack.

12. The method according to claim 9 ,

wherein the battery packs are connected or disconnected by a field effect transistor (FET), a relay or an insulated gate bipolar transistor (IGBT) of each battery pack.

13. A method for controlling the connection of a plurality of battery packs that controls connection of an additional battery pack to at least two parallel-connected battery packs, the method comprising:

determining the state of charge (SOC) of each of the parallel-connected battery packs and the additional battery pack;

comparing the SOCs of the parallel-connected battery packs and the additional battery pack;

when a difference in SOC between the parallel-connected battery packs and the additional battery pack falls out of a predetermined range, charging or discharging the parallel-connected battery packs so that the difference in SOC between the parallel-connected battery packs and the additional battery pack falls within the predetermined range; and

connecting the additional battery pack.

14. The method according to claim 13 , further comprising:

charging the entire battery pack connected in parallel after connecting the additional battery pack in parallel.

15. The method according to claim 13 ,

wherein the SOC of each battery pack is determined by a battery management system (BMS) provided in each battery pack.

16. The method according to claim 13 ,

wherein the battery packs are connected or disconnected by a field effect transistor (FET), a relay or an insulated gate bipolar transistor (IGBT) provided in each battery pack.