Battery pack and over-discharge protecting method thereof

• US 8,659,267 B2
• Filed: 02/22/2010
• Issued: 02/25/2014
• Est. Priority Date: 02/24/2009
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Yun, Changyong
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): TORRES RUIZ, JOHALI ALEJANDRA
• Application Number:
  US12/710,282
• Publication Number:
  US 20100214707A1
• Time in Patent Office: 1,464 Days
• Field of Search: 320/134
• US Class Current: 320/134
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence

Abstract

A battery pack includes a first battery stack having a plurality of battery cells connected in series, a second battery stack having a plurality of battery cells connected in series and connected in parallel to the first battery stack, a controller for sensing voltages of the plurality of battery cells of the first battery stack and the plurality of battery cells of the second battery stack and for outputting a fuse blowing signal when at least one of the sensed voltages is lower than a first reference voltage, and a fuse blowing unit for electrically decoupling the first and second battery stacks from an output terminal of the battery pack in response to the fuse blowing signal from the controller. A fuse blowing signal is also sent to the fuse blowing unit when the at least one of the sensed voltages is higher than a second reference voltage.

Claims

1. A battery pack comprising:

a first battery stack comprising a plurality of battery cells coupled in series;

a second battery stack comprising a plurality of battery cells coupled in series, and coupled in parallel with the first battery stack;

a controller for sensing voltages of the plurality of battery cells of the first battery stack and voltages of the plurality of battery cells of the second battery stack and for outputting a fuse blowing signal when at least one of the sensed voltages is lower than a first reference voltage; and

a fuse blowing unit for electrically decoupling the first battery stack and the second battery stack from an output terminal of the battery pack in response to the fuse blowing signal from the controller, the fuse blowing unit comprising;

a fuse between the first and second battery stacks and the output terminal;

a heating resistance coupled to the fuse to provide heat to the fuse;

a switch coupled to the heating resistance to allow a first electric current to flow into the heating resistance; and

a fuse blowing-proceed resistance coupled to the switch,

wherein the fuse blowing unit is configured to output a fuse blowing-proceed signal to the controller as a result of a second electric current flowing through the fuse blowing-proceed resistance when the first electric current flows into the heating resistance, and

wherein at least a portion of the second current flows through the switch.

2. The battery pack of claim 1, wherein the controller outputs the fuse blowing signal when the at least one of the sensed voltages is lower than the first reference voltage for a duration longer than a reference time.

3. The battery pack of claim 1, wherein the first battery stack and the second battery stack have substantially a same shape.

4. The battery pack of claim 1, wherein the first battery stack and the second battery stack have different shapes.

5. The battery pack of claim 1, wherein the first battery stack and the second battery stack have substantially a same capacity.

6. The battery pack of claim 1, wherein the first battery stack and the second battery stack have different capacities.

7. The battery pack of claim 1, wherein the fuse blowing unit further comprises a capacitor to filter an electric noise.

8. The battery pack of claim 1, wherein the fuse blowing unit further comprises a diode to prevent an electric noise from flowing into the controller.

9. The battery pack of claim 1, further comprising:

a first primary protection circuit between the first battery stack and the controller, for sensing the voltages of the plurality of battery cells of the first battery stack and for transmitting the sensed voltages to the controller; and

a first secondary protection circuit between the first battery stack and the fuse blowing unit, for sensing the voltages of the plurality of battery cells of the first battery stack and for outputting a secondary fuse blowing signal to the fuse blowing unit when at least one of the sensed voltages is higher than a second reference voltage.

10. The battery pack of claim 1, further comprising:

a second primary protection circuit between the second battery stack and the controller, for sensing the voltages of the plurality of battery cells of the second battery stack and for transmitting the sensed voltages to the controller; and

a second secondary protection circuit between the second battery stack and the fuse blowing unit, for sensing the voltages of the plurality of battery cells of the second battery stack and for outputting a secondary fuse blowing signal to the fuse blowing unit when at least one of the sensed voltages is higher than a second reference voltage.

11. A method of over-discharge protection of a battery pack, the battery pack comprising a first battery stack comprising a plurality of battery cells, and a second battery stack comprising a plurality of battery cells and coupled in parallel to the first battery stack, the method comprising:

determining a voltage of the first battery stack;

determining a voltage of the second battery stack;

blowing out a fuse between the first and second battery stacks and an output terminal of the battery pack when the voltage of the first battery stack or the voltage of the second battery stack is lower than a reference voltage by delivering a fuse blowing signal to a switch to cause a first current to travel through the fuse; and

outputting a fuse blowing-proceed signal when a second current flows through a fuse blowing-proceed resistance as a result of the switch being turned on,

wherein at least a portion of the second current flows through the switch.

12. The method of claim 11, wherein the determining the voltage of the first battery stack comprises comparing voltages of the plurality of battery cells of the first battery stack with the reference voltage to determine whether or not at least one of the voltages of the plurality of battery cells of the first battery stack is lower than the reference voltage.

13. The method of claim 11, wherein the determining the voltage of the second battery stack comprises comparing voltages of the plurality of battery cells of the second battery stack with the reference voltage to determine whether or not at least one of the voltages in the plurality of battery cells of the secondary battery stack is lower than the reference voltage.

14. The method of claim 11, further comprising:

determining whether or not the voltage of the first battery stack is lower than the reference voltage for a duration longer than a reference time.

15. The method of claim 11, further comprising:

determining whether or not the voltage of the second battery stack is lower than the reference voltage for a duration longer than a reference time.