Battery pack including input and output waveform modification capability

• US 6,324,339 B1
• Filed: 11/29/1999
• Issued: 11/27/2001
• Est. Priority Date: 11/29/1999
• Status: Expired due to Term

• Current Assignee: Energizer Brands, LLC (Energizer Holdings, Inc.)
• Original Assignee: Eveready Battery Company Incorporated (Energizer Holdings, Inc.)
• Inventors: Killebrew, Daniel L., Tibbs, Bobby L., Hudson, Richard A.
• Primary Examiner(s): Nappi, Robert E.
• Assistant Examiner(s): Duda, Rina I.
• Application Number:
  US09/450,870
• Time in Patent Office: 729 Days
• Field of Search: 388/811, 388/819, 388/937, 318/599, 318/139, 320/118, 320/135, 320/141, 320/145
• US Class Current: 388/809
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00032 characterised by data exchange
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack includes a plurality of electrochemical cells and a control circuit. The battery pack provides power to a tool in the form of a pulse width modulated waveform. The plurality of electrochemical cells provide a total output voltage. The control circuit is coupled to the plurality of electrochemical cells and receives a trigger signal from the tool. In response to the trigger signal, the control circuit determines whether a pulse width of the pulse width modulated waveform requires adjustment. Additionally, the control circuit can be configured to receive an indication of the total output voltage. In this case, the control circuit determines whether the pulse width of the pulse width modulated waveform requires adjustment based on the level of the total output voltage.

Claims

1. A battery pack for providing power to a tool in the form of a pulse width modulated waveform, comprising:

a plurality of electrochemical cells providing a total output voltage wherein a number of the electrochemical cells are connected in a serial manner to form a plurality of battery sticks, and wherein a number of the battery sticks are connected in parallel to form a plurality of battery stacks, and wherein a number of the battery stacks are connected in a serial manner to provide the total output voltage; and

a control circuit coupled to the plurality of electrochemical cells, the control circuit receiving a trigger signal from the tool, wherein the control circuit is adapted to change a pulse width of the pulse width modulated waveform in response to variations in the trigger signal, and wherein the control circuit also receives an indication of the total output voltage and is also adapted to change the pulse width of the pulse width modulated waveform in response to variations in the total output voltage, and wherein the control circuit is capable of providing a voltage indicator for either at least one battery stick or at least one battery stack.

2. The battery pack of claim 1, wherein the control circuit disconnects a battery charger from the battery pack if the voltage indicator exceeds a first predetermined voltage.

3. The battery pack of claim 2, wherein said first predetermined voltage is about 9.0 volts.

4. The battery pack of claim 3, wherein the control circuit disconnects a tool from the battery pack if the voltage level of one of the battery stacks goes below a second predetermined voltage.

5. The battery pack of claim 4, wherein said second predetermined voltage is about 4.0 volts.

6. A battery pack for providing power to a tool in the form of a pulse width modulated waveform, comprising:

a plurality of electrochemical cells providing a total output voltage; and

a control circuit coupled to the plurality of electrochemical cells, the control circuit receiving a trigger signal from the tool, wherein the control circuit is adapted to change a pulse width of the pulse width modulated waveform in response to variations in the trigger signal, and wherein the control circuit also receives an indication of the total output voltage and is also adapted to change the pulse width of the pulse width modulated waveform in response to variations in the total output voltage, and wherein the control circuit is capable of determining the magnitude of a charging current provided by a battery charger and is also adapted to modify the charging current to provide a substantially optimal charging current for the plurality of electrochemical cells; and

wherein the pulse width modulated waveform has a predetermined frequency in a range of about 800 Hz to 1 kHz.

7. A battery pack for providing power to a tool in the form of a pulse width modulated waveform, comprising:

a plurality of electrochemical cells providing a total output voltage, wherein a number of the electrochemical cells are connected in a serial manner to form a plurality of battery sticks, and wherein a number of the battery sticks are connected in parallel to form a plurality of battery stacks, and wherein a number of the battery stacks are connected in a serial manner to provide the total output voltage; and

a control circuit coupled to the plurality of electrochemical cells, the control circuit receiving a trigger signal from the tool, wherein the control circuit is adapted to change a pulse width of the pulse width modulated waveform in response to variations in the trigger signal, and wherein the control circuit also receives an indication of the total output voltage and is also adapted to change the pulse width of the pulse width modulated waveform in response to variations in the total output voltage; and

at least one temperature sensor coupled to the control circuit providing a temperature indication for either at least one individual cell or at least one stick of cells, wherein the control circuit prevents a battery charger from charging the battery pack if the temperature indication falls below a first predetermined temperature.

8. The battery pack of claim 7, wherein said first predetermined temperature is about 0 degrees Celsius.

9. The battery pack of claim 8, wherein the control circuit prevents a battery charger from charging the battery pack if the temperature indication rises above a second predetermined temperature.

10. The battery pack of claim 9, wherein said second predetermined temperature is about 40 degrees Celsius.

11. The battery pack of claim 10 wherein the control circuit prevents the battery pack from providing power to the tool if the temperature indication rises above a third predetermined temperature.

12. The battery pack of claim 11 wherein said third predetermined temperature is about 60 degrees Celsius.

13. A battery pack for supplying power to an electrical device, said battery pack comprising:

a housing;

a plurality of electrochemical cells disposed within said housing; and

a control circuit disposed in said housing and operatively coupled to said plurality of electrochemical cells, said control circuit receiving a power demand signal from the electrical device indicating a voltage level to be supplied from the battery pack to the electrical device, said control circuit varying the voltage level output from the battery pack in response to said power demand signal, wherein said control circuit generates a pulse width modulated waveform having an average voltage per unit time that corresponds to the power demand signal from the electrical device, wherein said control circuit monitors the voltage of said cells and controls the charging and discharging of the cells in response to the voltage of the cells, and wherein said control circuit includes a switch coupled between the cells and an output terminal of the battery pack for selectively modulating the supply of power from the cells through the output terminal.

14. The battery pack as defined in claim 13, wherein said switch is controlled to modulate the supply of power in response to the voltage of the cells.

15. The battery pack as defined in claim 13, wherein said switch is controlled to modulate the supply of power in response to the power demand signal.

16. The battery pack as defined in claim 13, wherein said switch is controlled to prevent the cells from being further discharged when the voltage of the cells falls below a threshold value.

17. A battery pack for providing power to a tool in the form of a pulse modulated waveform, comprising:

a plurality of electrochemical cells providing a total output voltage, wherein a number of the electrochemical cells are connected in a serial manner to form a plurality of battery sticks, and wherein a number of the battery sticks are connected in parallel to form a plurality of battery stacks, and wherein a number of battery stack are connected in a serial manner to provide the total output voltage; and

a control circuit coupled to the plurality of electrochemical cells, the battery pack receiving a charging current from a battery charger, wherein the control circuit receives an indication of the charging current provided by the battery charger, and wherein the control circuit is adapted to modify the charging current to provide a substantially optimal charging current for the plurality of electrochemical cells, wherein the control circuit also receives a trigger signal from the tool and is adapted to change a pulse width of the pulse width modulated waveform in response to variations in the trigger signal, wherein the control circuit also receives an indication of the total output voltage and is also adapted to change the pulse width of the pulse width modulated waveform in response to variations in the total output voltage, and wherein the control circuit is capable of providing a voltage indicator for either at least one battery stick or at least one battery stack.

18. The battery pack of claim 17, wherein the control circuit disconnects a battery charger from the battery pack if the voltage indicator exceeds a first predetermined voltage.

19. The battery pack of claim 18, wherein said first predetermined voltage is about 9.0 volts.

20. The battery pack of claim 19, wherein the control circuit disconnects a tool from the battery pack if the voltage level of one of the battery sticks goes below a second predetermined voltage.

21. The battery pack of claim 20, wherein said second predetermined voltage is about 4.0 volts.

22. A battery pack for providing power to a tool in the form of a pulse width modulated waveform, comprising:

a plurality of electrochemical cells providing a total output voltage, wherein a number of the electrochemical cells are connected in a serial manner to form a plurality of battery sticks, and wherein a number of the battery sticks are connected in parallel to form a plurality of battery stacks, and wherein a number of battery stack are connected in a serial manner to provide the total output voltage; and

a control circuit coupled to the plurality of electrochemical cells, the battery pack receiving a charging current from a battery charger, wherein the control circuit receives an indication of the charging current provided by the battery charger, and wherein the control circuit is adapted to modify the charging current to provide a substantially optimal charging current for the plurality of electrochemical cells, wherein the control circuit also receives a trigger signal from the tool and is adapted to change a pulse width of the pulse width modulated waveform in response to variations in the trigger signal, wherein the control circuit also receives an indication of the total output voltage and is also adapted to change the pulse width of the pulse width modulated waveform in response to variations in the total output voltage; and

at least one temperature sensor coupled to the control circuit providing a temperature indication for either at least one cell or at least one battery stick, wherein the control circuit prevents a battery charger from charging the battery pack if the temperature indication falls below a first predetermined temperature.

23. The battery pack of claim 22, wherein said first predetermined temperature is about 0 degrees Celsius.

24. The battery pack of claim 23, wherein the control circuit prevents a battery charger from charging the battery pack if the temperature indication rises above a second predetermined temperature.

25. The battery pack of claim 24, wherein said second predetermined temperature is about 40 degrees Celsius.

26. The battery pack of claim 25, wherein the control circuit prevents the battery pack from providing power to the tool if the temperature indication rises above a third predetermined temperature.

27. The battery pack of claim 26, wherein said third predetermined temperature is about 60 degrees Celsius.