Automatic battery charger with voltage controlled charging and ripple voltage test

• US 6,586,913 B2
• Filed: 06/26/2001
• Issued: 07/01/2003
• Est. Priority Date: 06/30/2000
• Status: Active Grant

• Current Assignee: Associated Equipment Corporation (Associated Equipment)
• Original Assignee: Associated Equipment Corporation (Associated Equipment)
• Inventors: Rolfes, Michael J.
• Primary Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/891,816
• Publication Number:
  US 20020033691A1
• Time in Patent Office: 735 Days
• Field of Search: 320/162, 320/139, 320/143, 320/163, 320/164
• US Class Current: 320/162
• CPC Class Codes: H02J 7/1446 in response to parameters of a vehicle
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

A method and apparatus for charging a battery. A voltage controlled charger applies an initial charging signal and measures the battery terminal voltage. If the measured terminal voltage exceeds an upper threshold, the charger reduces the charging signal. If the measured terminal voltage falls below a lower threshold, the charger increases the charging signal. If the measured terminal voltage falls between the upper and the lower thresholds, the charger maintains the charging signal. Thereby, the charger substantially prevents the charging signal from exceeding the battery gassing potential during the charging process. The method and apparatus also desulfate deeply discharged batteries. The method and apparatus monitor a ripple voltage associated with the battery terminals to assess battery charge acceptance and battery quality. The amount of tolerable ripple voltage preferably decreases as the charging process proceeds.

Claims

1. A method of charging a battery having battery terminals, said method comprising:

(a) initiating a battery charging process;

(b) applying a charging signal to the battery terminals;

(c) measuring a battery terminal voltage associated with the battery;

(d) determining a ripple voltage component of the measured battery terminal voltage;

(e) comparing the determined ripple voltage component to a ripple voltage limit having a first value;

(f) decreasing the ripple voltage limit from the first value to a second value if the determined ripple voltage component is less the first value of the ripple voltage limit; and

(g) terminating the battery charging process if the determined ripple voltage component is greater than the ripple voltage limit.

2. The method of claim 1 further comprising:

(h) repeating steps (b), (c), (d), (e), (f), and (g) until the measured battery terminal voltage is greater than or equal to an end of charge voltage threshold or the charging process is terminated at step (g).

3. The method of claim 1 further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile to the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

4. The method of claim 1 wherein the battery further comprises an electrolyte and has a gassing potential at which the electrolyte tends to vaporize, said method further comprising:

comparing the measured battery terminal voltage to a voltage threshold;

determining a difference between the battery terminal voltage and the voltage threshold; and

adjusting the charging signal as a function of the difference between the battery terminal voltage and the voltage threshold.

5. The method of claim 4 further comprising maintaining the charging signal such that the measured battery terminal voltage substantially remains below the gassing potential.

6. The method of claim 4 further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile to the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

7. The method of claim 1 wherein the applied charging signal comprises an applied charging voltage, said method further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a desulfation pulse charge charging voltage profile to the battery terminals for a first time interval;

applying a desulfation charge acceptance charging voltage profile to the battery terminals for a second time interval;

executing a nonsulfated battery charging profile upon completion of the desulfation pulse charge charging voltage profile and the desulfation charge acceptance charging voltage profile comprising the steps of;

comparing the measured battery terminal voltage to an upper voltage threshold;

comparing the measured battery terminal voltage to a lower voltage threshold;

increasing the applied charging voltage if the measured battery terminal voltage is below the lower voltage charging threshold;

decreasing the applied charging voltage if the measured battery terminal voltage is above the upper voltage charging threshold; and

performing a termination test and terminating the battery charging method if a termination criterion is satisfied.

8. The method of claim 1 wherein the battery further comprises an electrolyte and has a gassing potential at which the electrolyte tends to vaporize, and wherein the applied charging signal comprises an applied charging voltage, said method further comprising:

comparing the measured battery terminal voltage to an upper voltage threshold;

comparing the measured battery terminal voltage to a lower voltage threshold;

increasing the applied charging voltage if the measured battery terminal voltage is below the lower voltage threshold; and

decreasing the applied charging voltage if the measured battery terminal voltage is above the upper voltage threshold.

9. The method of claim 8 further comprising maintaining the applied charging voltage when the measured battery terminal voltage is above the lower voltage threshold and below the upper voltage threshold such that the measured battery terminal voltage substantially remains below the gassing potential.

10. The method claim 8 further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile to the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

11. A method of charging a battery for a charging time, said battery having battery terminals, said method comprising:

initiating a battery charging process;

applying a charging signal to the battery terminals;

measuring a battery terminal voltage associated with the battery;

determining a ripple voltage component of the measured battery terminal voltage;

comparing the determined ripple voltage component to a ripple voltage limit having a first value;

terminating the charging process if the determined ripple voltage component is greater than the ripple voltage limit;

adjusting the ripple voltage limit as a function of the charging time such that the ripple voltage limit decreases from the first value to a second value as the charging time increases.

12. The method of claim 11 further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile to the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

13. The method of claim 11 wherein the battery further comprises an electrolyte and has a gassing potential at which the electrolyte tends to vaporize, said method further comprising:

comparing the measured battery terminal voltage to a voltage threshold;

determining a difference between the battery terminal voltage and the voltage threshold; and

adjusting the charging signal as a function of the difference between the battery terminal voltage and the voltage threshold.

14. The method of claim 13 further comprising maintaining the charging signal such that the measured battery terminal voltage substantially remains below the gassing potential.

15. The method of claim 13 further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile to the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

16. The method of claim 11 wherein the applied charging signal comprises an applied charging voltage, said method further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a desulfation pulse charge charging voltage profile to the battery terminals for a first time interval;

applying a desulfation charge acceptance charging voltage profile to the battery terminals for a second time interval;

executing a nonsulfated battery charging profile upon completion of the desulfation pulse charge charging voltage profile and the desulfation charge acceptance charging voltage profile comprising the steps of;

comparing the measured battery terminal voltage to an upper voltage threshold;

comparing the measured battery terminal voltage to a lower voltage threshold;

increasing the applied charging voltage if the measured battery terminal voltage is below the lower voltage charging threshold;

decreasing the applied charging voltage if the measured battery terminal voltage is above the upper voltage charging threshold; and

performing a termination test and terminating the battery charging method if a termination criterion is satisfied.

17. The method of claim 11 wherein the battery further comprises an electrolyte and has a gassing potential at which the electrolyte tends to vaporize, and wherein the applied charging signal comprises an applied charging voltage, said method further comprising:

comparing the measured battery terminal voltage to an upper voltage threshold;

comparing the measured battery terminal voltage to a lower voltage threshold;

increasing the applied charging voltage if the measured battery terminal voltage is below the lower voltage threshold; and

decreasing the applied charging voltage if the measured battery terminal voltage is above the upper voltage threshold.

18. The method of claim 17 further comprising maintaining the applied charging voltage if the measured battery terminal voltage is above the lower voltage threshold and below the upper voltage threshold such that the measured battery terminal voltage substantially remains below the gassing potential.

19. The method of claim 17 further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile to the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

20. A battery charger for charging a battery for a charging time, the battery including battery terminals, an electrolyte, and having a gassing potential at which the electrolyte tends to vaporize, said battery charger comprising:

a controller selectively providing a power control signal;

the controller including a monitoring function monitoring a voltage at the battery terminals;

a power application circuit applying a charging signal to the battery terminals in response to the power control signal;

the controller including a measuring function selectively measuring a ripple voltage associated with the voltage monitored at the battery terminals;

the controller including a ripple voltage comparing function comparing the monitored ripple voltage to a ripple voltage limit having a first value; and

the controller including a limit adjusting function adjusting the ripple voltage limit as a function of the charging time, wherein the ripple voltage limit decreases from the first value to a second value as the charging time increases.

21. The battery charger of claim 20 wherein the controller includes a terminating function which terminates the power control signal when the monitored ripple voltage exceeds the ripple voltage limit thereby terminating the application of the charging signal to the battery terminals.

22. The battery charger of claim 21 wherein the controller includes a power control adjusting function which adjusts the power control signal in response to the voltage monitored at the battery terminals to substantially inhibit the power application circuit from applying the charging signal at a level above the battery gassing potential.

23. The battery charger of claim 22 wherein the controller includes a battery terminal comparing function which compares the voltage monitored at the battery terminals to a sulfation threshold voltage to determine the charge state of the battery and varies the power control signal such that the power application circuit applies a pulse charge to the battery terminals when the voltage monitored at the battery terminals is less than the sulfation threshold voltage.

24. A method of charging a battery including battery terminals, an electrolyte, and having a predetermined gassing potential at which the electrolyte tends to vaporize, the method comprising:

applying a charging signal to the battery terminals;

measuring a battery terminal voltage associated with the battery;

comparing the measured battery terminal voltage to a voltage threshold; and

adjusting the applied charging signal as a function of the measured battery terminal voltage such that the measured battery terminal voltage substantially remains below the predetermined gassing potential;

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile to the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

25. A method of charging a battery including battery terminals, an electrolyte, and having a predetermined gassing potential at which the electrolyte tends to vaporize, the method comprising:

applying a charging signal to the battery terminals;

measuring a battery terminal voltage associated with the battery;

comparing the measured battery terminal voltage to a voltage threshold; and

adjusting the applied charging signal as a function of the measured battery terminal voltage such that the measured battery terminal voltage substantially remains below the predetermined gassing potential;

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a desulfation pulse charge charging voltage profile to the battery terminals for a first time interval; and

applying a desulfation charge acceptance charging voltage profile to the battery terminals for a second time interval.

26. A method of charging a battery including battery terminals, an electrolyte, and having a predetermined gassing potential at which the electrolyte tends to vaporize, the method comprising:

applying an initial charging voltage to the battery terminals;

measuring at the battery terminals a battery terminal voltage associated with the battery;

comparing the measured battery terminal voltage to an upper voltage threshold;

comparing the measured battery terminal voltage to a lower voltage threshold;

increasing the applied charging voltage if the measured battery terminal voltage is less than the lower voltage threshold;

decreasing the applied charging voltage if the measured battery terminal voltage above the upper voltage threshold; and

maintaining the applied charging voltage if the measured battery terminal voltage is above the lower voltage threshold and below the upper voltage threshold, such that the measured battery terminal voltage substantially remains below the predetermined gassing potential.

27. The method of claim 26 further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile to the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

28. The method of claim 26 further comprising:

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a desulfation pulse charge charging voltage profile to the battery terminals for a first time interval; and

applying a desulfation charge acceptance charging voltage profile to the battery terminals for a second time interval.

29. A battery charger for charging a battery including battery terminals, an electrolyte, and having a predetermined gassing potential at which the electrolyte tends to vaporize, said battery charger comprising:

a controller selectively providing a power control signal;

the controller including a monitoring function monitoring a voltage at the battery terminals;

a power application circuit selectively applying a charging signal to the battery terminals in response to the power control signal; and

the controller including;

an adjusting function adjusting the power control signal in response to the voltage monitored at the battery terminals such that the power control signal is adjusted to substantially inhibit the power application circuit from applying the charging signal at a level above the predetermined gassing potential; and

a comparing function which compares the voltage monitored at the battery terminals to a sulfation threshold voltage to determine the charge state of the battery, said controller varying the power control signal such that the power application circuit applies a pulse charge to the battery terminals when the voltage monitored at the battery terminals is less than the sulfation threshold voltage.

30. A method of charging a battery having battery terminals, said method comprising:

initiating a battery charging process;

applying a charging signal to the battery terminals;

measuring a battery terminal voltage associated with the battery;

determining a ripple voltage component of the measured battery terminal voltage;

comparing the determined ripple voltage component to a ripple voltage limit having a first value;

adjusting the ripple voltage limit from the first value to a second value as a function of a difference between the determined ripple voltage component and the ripple voltage limit;

determining if the battery is sulfated;

performing a desulfation process if the battery is determined to be sulfated, said desulfation process comprising;

applying a pulse charge voltage charging profile the battery terminals; and

applying a charge acceptance charging voltage profile to the battery terminals upon completion of the application of the pulse charge voltage charging profile.

31. A method of charging a battery comprising battery terminals, an electrolyte, and having a gassing potential at which the electrolyte tends to vaporize, said method comprising:

initiating a battery charging process;

applying a charging signal to the battery terminals;

measuring a battery terminal voltage associated with the battery;

determining a ripple voltage component of the measured battery terminal voltage;

comparing the determined ripple voltage component to a ripple voltage limit having a first value;

adjusting the ripple voltage limit from the first value to a second value as a function of a difference between the determined ripple voltage component and the ripple voltage limit;

comparing the measured battery terminal voltage to a voltage threshold;

determining a difference between the battery terminal voltage and the voltage threshold; and

adjusting the charging signal as a function of the difference between the battery terminal voltage and the voltage threshold such that the measured battery terminal voltage substantially remains below the gassing potential.

32. A method of charging a battery comprising battery terminals, an electrolyte, and having a gassing potential at which the electrolyte tends to vaporize, said method comprising:

initiating a battery charging process;

applying a charging voltage to the battery terminals;

measuring a battery terminal voltage associated with the battery;

determining a ripple voltage component of the measured battery terminal voltage;

comparing the determined ripple voltage component to a ripple voltage limit having a first value;

adjusting the ripple voltage limit from the first value to a second value as a function of a difference between the determined ripple voltage component and the ripple voltage limit;

comparing the measured battery terminal voltage to an upper voltage threshold;

comparing the measured battery terminal voltage to a lower voltage threshold;

increasing the applied charging voltage if the measured battery terminal voltage is below the lower voltage threshold; and

decreasing the applied charging voltage if the measured battery terminal voltage is above the upper voltage threshold.