Battery pack and method of controlling charging of battery pack

• US 20110121789A1
• Filed: 11/16/2010
• Published: 05/26/2011
• Est. Priority Date: 11/20/2009
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Okada, Testyua, Susumu, Segawa, Yang, Jong-Woon, Park, In-Kyu, Kim, Jin-Wan
• Granted Patent: US 8,513,922 B2
• Time in Patent Office: Days
• US Class Current: 320/152
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

A battery pack includes a battery cell, a charge-blocking unit, a voltage sensing and balancing circuit, and a microcomputer, the microcomputer including a controller that detects at least one selected from the group of abnormal analog-to-digital conversion, abnormal voltage, and abnormal temperature of the battery cell, the controller outputting a charge control signal to the charge-blocking unit to inhibit charging of the battery cell.

Claims

1. A battery pack, comprising:

a battery cell;

a charge-blocking unit;

a voltage sensing and balancing circuit; and

a microcomputer, the microcomputer including a controller configured to detect at least one selected from the group of abnormal analog-to-digital conversion, abnormal voltage, and abnormal temperature of the battery cell, the controller configured to output a charge control signal to the charge-blocking unit to inhibit charging of the battery cell.

2. The battery pack as claimed in claim 1, wherein:

the microcomputer further includes an analog-to-digital (A/D) converter that converts analog voltage, temperature, and current measurements from the battery cell into digital output values, and

the controller outputs a charge control signal to the charge-blocking unit if the difference between a measurement value obtained by inputting a voltage of a zenor diode to the A/D converter and a reference value recorded during an initial test of the microcomputer is equal to or greater than a first threshold.

3. The battery pack as claimed in claim 1, wherein:

the battery pack includes a plurality of battery cells, and

the controller outputs a charge control signal to the charge-blocking unit if a difference between a sum of voltages of the plurality of battery cells and a voltage of the battery pack is equal to or greater than a second threshold.

4. The battery pack as claimed in claim 3, wherein:

the microcomputer further includes a current measuring unit, and

the controller outputs a charge control signal to the charge-blocking unit if the difference between the sum of voltages of each of the plurality of battery cells and the voltage of the battery pack is equal to or greater than a second threshold, and the measured current is equal to or less than a third threshold.

5. The battery pack as claimed in claim 1, wherein:

the microcomputer further includes a temperature measuring unit for measuring the temperature of the microcomputer, and

the controller outputs a charge control signal to the charge-blocking unit if a difference between the temperature of the battery cell and the temperature of the microcomputer is equal to or greater than a fourth threshold.

6. The battery pack as claimed in claim 5, wherein the controller outputs a charge control signal to the charge-blocking unit if the difference between the temperature of the battery cell and the temperature of the microcomputer is equal to or greater than the fourth threshold, and a temperature change within a time period during which the temperature is measured is equal to or less than a fifth threshold.

7. The battery pack as claimed in claim 1, wherein the controller detects, at least twice, at least one selected from the group of abnormal analog-to-digital conversion of the microcomputer, abnormal voltage, and abnormal temperature of the battery cells.

8. The battery pack as claimed in claim 1, wherein the charge-blocking unit includes a fuse disposed between the battery cell and a charging terminal for inhibiting overcharge, a heating resistor for blowing the fuse, and a switch that is turned on or off according to the charge control signal output by the controller.

9. The battery pack as claimed in claim 1, wherein the battery pack is an electric power tool battery pack.

10. A method of controlling charge of a battery pack that includes a battery cell, a charge-blocking unit, a voltage sensing and balancing circuit, and a microcomputer, the method comprising:

detecting at least one selected from the group of abnormal analog-to-digital conversion of the microcomputer, abnormal voltage, and abnormal temperature of the battery cell;

outputting a charge control signal to the charge-blocking unit according to the detected abnormality; and

inhibiting charging of the battery pack according to the charge control signal.

11. The method as claimed in claim 10, wherein the detecting includes:

measuring an analog-to-digital conversion value by inputting a voltage of a zenor diode to an analog-to-digital (A/D) converter;

determining whether a difference between the measured value and a reference value recorded during an initial test of the microcomputer is equal to or greater than a first threshold; and

outputting a charge control signal to the charge-blocking unit if the difference is equal to or greater than the first threshold.

12. The method as claimed in claim 10, wherein the battery pack includes a plurality of battery cells, and the detecting includes:

measuring a voltage of each of the battery cells and a voltage of the battery pack;

determining whether a difference between a sum of the voltages of each of the battery cells and the voltage of the battery pack is equal to or greater than a second threshold; and

outputting a charge control signal to the charge-blocking unit if the difference is equal to or greater than the second threshold.

13. The method as claimed in claim 12, wherein:

the detecting further includes measuring a current of the battery pack, and

the outputting includes outputting a charge control signal to the charge-blocking unit if the difference is equal to or greater than the second threshold and the measured current is equal to or less than a third threshold.

14. The method as claimed in claim 10, wherein the detecting further includes:

measuring a temperature of the battery cell and a temperature of the microcomputer;

determining whether the difference between the temperature of the battery cell and the temperature of the microcomputer is equal to or greater than a fourth threshold; and

outputting a charge control signal to the charge-blocking unit if the difference is equal to or greater than the fourth threshold.

15. The method as claimed in claim 14, wherein:

the detecting further includes calculating a temperature change for a time period during which the temperature is measured if the difference is equal to or greater than the fourth threshold, and

the outputting includes outputting a charge control signal to the charge-blocking unit if the temperature change is equal to or less than a fifth threshold.

16. The method as claimed in claim 10, wherein the detecting further includes performing, at least twice, the detecting of at least one selected from the group of abnormal analog-to-digital conversion of the microcomputer, abnormal voltage, and abnormal temperature of the battery cells.

17. The method as claimed in claim 10, wherein the battery pack is an electric power tool battery pack.