Method and apparatus for charging batteries

• US 6,489,752 B1
• Filed: 04/19/2002
• Issued: 12/03/2002
• Est. Priority Date: 05/25/2001
• Status: Expired due to Fees

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Watts, Fred S., Trinh, Danh T.
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US10/126,568
• Publication Number:
  US 20020175658A1
• Time in Patent Office: 228 Days
• Field of Search: 320/127, 320/128, 320/137, 320/150, 320/153
• US Class Current: 320/150
• CPC Class Codes: H02J 7/007194 of the battery

Abstract

The charging method includes providing a current to the battery pack, sensing first and second battery temperatures, determining a first temperature change rate between the first and second battery temperatures, sensing a third battery temperature, determining a second temperature change between the second and third battery temperatures, and disabling termination of the charging method based on a temperature-based scheme if the first temperature change rate is equal to or exceeds a first predetermined threshold and the second temperature change rate is equal to or exceeds a second predetermined threshold.

Claims

1. A method for charging a battery comprising:

providing a current to the battery;

sensing first and second battery temperatures;

determining a first temperature change rate between the first and second battery temperatures;

sensing a third battery temperature;

determining a second temperature change between the second and third battery temperatures; and

disabling termination of the charging method based on a temperature-based scheme if the first temperature change rate is equal to or exceeds a first predetermined threshold and the second temperature change rate is equal to or exceeds a second predetermined threshold.

2. The method of claim 1, wherein the battery has a thermistor.

3. The method of claim 2, wherein the thermistor is outside of an airflow.

4. The method of claim 2, wherein the thermistor is inside an airflow.

5. The method of claim 1, wherein the first predetermined threshold is about 0.0380 °

Celsius.

6. The method of claim 1, wherein the second predetermined threshold is about 0.0770 °

Celsius.

7. The method of claim 1, wherein the second predetermined threshold is about two times larger than the first predetermined threshold.

8. The method of claim 1, wherein the temperature-based scheme is a temperature change rate termination scheme or an absolute temperature scheme.

9. A method for charging a battery comprising:

providing a current to the battery;

sensing first and second battery temperatures;

determining a first temperature change rate between the first and second battery temperatures;

sensing a third battery temperature;

determining a second temperature change between the second and third battery temperatures; and

disabling termination of the charging method based on a temperature-based scheme if the first temperature change rate is equal to or below a first predetermined threshold and the second temperature change rate is equal to or below a second predetermined threshold.

10. The method of claim 9, wherein the battery has a thermistor.

11. The method of claim 10, wherein the thermistor is outside of an airflow.

12. The method of claim 10, wherein the thermistor is inside an airflow.

13. The method of claim 9, wherein the first predetermined threshold is about 0.038°

Celsius.

14. The method of claim 9, wherein the second predetermined threshold is about 0.0770°

Celsius.

15. The method of claim 9, wherein the second predetermined threshold is about two times larger than the first predetermined threshold.

16. The method of claim 9, wherein the temperature-based scheme is a temperature change rate termination scheme or an absolute temperature scheme.