Energy storage device and method for controlling the same
An energy storage device and methods for controlling the same are disclosed. The energy storage device can include a connector to or from which at least one battery pack is attached or detached, a power converter that converts external input power into DC power in a charge mode, and a switching unit that performs a switching operation such that the DC power converted by the power converter is charged in a first battery pack attached to the connector in the charge mode. Energy storage device can also include a controller that controls the switching unit to turn off electrical connections between the energy storage device and the first battery pack and a second battery pack for a predetermined off period when the first and second battery packs are attached to the connector. Accordingly, when a battery pack is attached or detached, a surge of inrush current may be reduced.
1. An energy storage device comprising:
at least one battery pack;
a connector to or from which the at least one battery pack is attached or detached;
a power converter that converts external input power into direct current (DC) power in a charge mode;
a switching unit to perform a switching operation that charges a first battery pack of the at least one battery pack with the DC power converted by the power converter, the first battery pack attached to the connector in the charge mode; and
a controller to control the switching unit by turning off electrical connections between the power converter and the first battery pack, or between the power converter and a second battery pack of the at least one battery pack for a predetermined off period when the first and second battery packs are attached to the connector,
wherein each battery pack includes:
a connector including a positive power terminal, a negative power terminal and a control signal terminal;
a battery cell unit; and
a battery controller configured to control the battery cell unit,
wherein when the second battery pack is attached under the condition that the first battery pack operates in the charge mode, the controller controls to turn off a first switch and a second switch of the switching unit during a first off period,
wherein after the first off period, the controller controls to keep off the first switch and turn on the second switch such that the second battery pack, not the first battery pack, operates in the charge mode.
2. The energy storage device according to claim 1 , wherein the controller performs a control operation during the charge mode that selects and charges one of the first and second battery packs with the converted DC power after the predetermined off period elapses, the selection based on which of the first and second battery packs has a lower level of DC power.
3. The energy storage device according to claim 1 , wherein the controller controls the switching unit to turn off the electrical connections between the energy storage device and the first and second battery packs for the predetermined off period when the second battery pack is detached.
4. The energy storage device according to claim 1 , wherein the controller sets a length of the off period to be longer when a number of battery packs attached to the energy storage device increases.
5. The energy storage device according to claim 3 , wherein the controller sets a length of the off period to be longer when the second battery pack is attached to the energy storage device in comparison to when the second battery pack is detached from the energy storage device.
6. The energy storage device according to claim 1 ,
wherein the connector includes positive power connection terminal, negative power connection terminal and control signal connection terminal, which are coupled with the positive power terminal, the negative power terminal and the control signal terminal of the attached battery pack, respectively,
wherein the controller performs a control operation that power balances a plurality of battery packs based on a levels of DC power stored in the respective battery packs when the plurality of battery packs are attached to the connector,
wherein the levels of DC power is received through control signal connection terminal from each battery pack.
7. The energy storage device according to claim 1 , wherein the power converter converts DC power supplied from the first or second battery packs attached to the connector and externally output a result of the conversion during a discharge mode.
8. The energy storage device according to claim 7 , wherein the controller performs a control operation during the discharge mode that selects and supplies DC power from one of the first or second battery packs to the power converter after the predetermined off period elapses, the selection based on which of the first and second battery packs has a higher level of DC power.
9. A method for controlling an energy storage device to or from which at least one battery pack is attachable or detachable, the method comprising:
converting, by a power converter, external input power into direct current (DC) power;
charging the converted DC power in a first battery pack of the at least one battery pack attached to the energy storage device; and
turning off electrical connections between the power converter and the first battery pack, or between the power converter and a second battery pack of the at least one battery pack for a predetermined off period when the second battery pack is attached to the energy storage device,
wherein each battery pack includes:
a connector including a positive power terminal, a negative power terminal and a control signal terminal;
a battery cell unit; and
a battery controller configured to control the battery cell unit,
wherein when the second battery pack is attached under the condition that the first battery pack operates in the charge mode, a first switch and a second switch of the switching unit are turned off during a first off period,
wherein after the first off period, the first switch is kept off and the second switch is turned on such that the second battery pack, not the first battery pack, operates in the charge mode.
10. The method according to claim 9 , further comprising:
charging the converted DC power in the second battery pack after the predetermined off period.
11. The method according to claim 9 , further comprising:
charging one of the first or second battery packs based on which of the first and second battery packs has lower of a lower level of converted DC power stored therein after the predetermined off period.
12. The method according to claim 11 , further comprising:
turning off the electrical connections between the energy storage device and the first and second battery packs for the predetermined off period when the second battery pack is detached from the energy storage device.
13. The method according to claim 9 , wherein a length of the off period corresponds to a number of battery packs attached to the energy storage device.
14. The method according to claim 12 , wherein a length of the off period is set to be longer when the second battery pack is attached to the energy storage device in comparison to when the second battery pack is detached from the energy storage device.
15. A method for controlling an energy storage device to or from which at least one battery pack is attachable or detachable, the method comprising:
Receiving, by a connector, direct current (DC) power from a first battery pack of the at least one battery pack attached to the energy storage device;
Converting, by a power converter, the DC power received from the first battery pack and externally outputting a result of the conversion; and
turning off electrical connections between the power converter and the first battery pack, or between the power converter and a second battery pack of the at least one battery pack for a predetermined off period when the second battery pack is attached to the energy storage device,
wherein each battery pack includes:
a connector including a positive power terminal, a negative power terminal and a control signal terminal;
a battery cell unit; and
a battery controller configured to control the battery cell unit,
wherein when the second battery pack is attached under the condition that the first battery pack operates in the charge mode, a first switch and a second switch of the switching unit are turned off during a first off period,
wherein after the first off period, the first switch is kept off and the second switch is turned on such that the second battery pack, not the first battery pack, operates in the charge mode.
16. The method according to claim 15 , further comprising:
receiving DC power from the second battery pack after the predetermined off period; and
converting the DC power received from the second battery pack and externally outputting a result of the conversion.
17. The method according to claim 15 , further comprising:
receiving DC power from one of the first or second battery packs based on which of the first and second battery packs has a higher level of DC power stored therein after the predetermined off period.
18. The method according to claim 16 , further comprising:
turning off the electrical connections between the energy storage device and the first and second battery packs for the predetermined off period when the second battery pack is detached from the energy storage device.
19. The method according to claim 15 , wherein the off period increases when a number of battery packs attached to the energy storage device increases.
20. The method according to claim 18 , wherein a length of the off period is set to be longer when the second battery pack is attached to the energy storage device in comparison to when the second battery pack is detached from the energy storage device.
21. The energy storage device according to claim 1 ,
wherein each battery pack further includes a temperature adjuster,
wherein the temperature adjuster includes temperature sensing means to sense temperature of the battery cell unit and fan driving means to drive a fan based on the sensed temperature so as to control the temperature of the battery cell unit.