Power supply charging method and device

• US 20060164038A1
• Filed: 01/25/2006
• Published: 07/27/2006
• Est. Priority Date: 01/25/2005
• Status: Active Grant

• Current Assignee: Victhom Laboratory Inc (Ergoresearch Ltd.)
• Original Assignee: Victhom Human Bionics Inc. (Ergoresearch Ltd.)
• Inventors: Bedard, Stephane, Poulin, Michael, Demers, Remi
• Granted Patent: US 7,786,699 B2
• Time in Patent Office: Days
• US Class Current: 320/116
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection

Abstract

A power supply charging method and device for charging a power supply having a predetermined number of battery cells divided into at least two battery cell groups. The method comprises the steps of, for each battery cell group, applying a voltage across the battery cell group until one condition selected from the group consisting of the voltage of a battery cell exceeding a first threshold and the current of the cell group dropping below a second threshold, is met and verifying that each of the predetermined number of battery cells has a similar voltage. When the verification of the battery cells voltage determines that at least one battery cell has a voltage departing from the voltage of the other battery cells by more than a predetermine value, the voltage of the other cells is decreased and the previous steps are repeated. The method may further comprise the step of, for each battery cell group, applying a voltage across the battery cell group until the current of the battery cell group drops below a third threshold and stays below the third threshold for a predetermined period of time. As device implementing the charging method is also described.

Claims

1. A method of charging a power supply having a predetermined number of battery cells divided into at least two battery cell groups, the method comprising the steps of:

a—

for each battery cell group, applying a voltage across the battery cell group until one condition selected from the group consisting of the voltage of a battery cell exceeding a first threshold and the current of the cell group dropping below a second threshold, is met;

b—

verifying that each of the predetermined number of battery cells has a similar voltage;

c—

when the verification of the battery cells voltage in step b determines that at least one battery cell has a voltage departing from the voltage of the other battery cells by more than a predetermine value, decreasing the voltage of the other cells and returning to step a.

2. A method according to claim 1, wherein the first threshold is set to 4.2V.

3. A method according to claim 1, wherein the second threshold is set to C/10, C being a current corresponding to a nominal capacity of the battery cells.

4. A method according to claim 1, further comprising the step of:

d—

for each battery cell group, applying a voltage across the battery cell group until the current of the battery cell group drops below a third threshold and stays below the third threshold for a predetermined period of time.

5. A method according to claim 4, wherein the third threshold is set to C/10, C being a current corresponding to a nominal capacity of the battery cells.

6. A method according to claim 4, wherein the predetermined period of time is set to 10 minutes.

7. A method according to claim 1, wherein step c is repeated up to a predetermined maximum number of times.

8. A method according to claim 7, wherein the predetermined maximum number of times is 3.

9. A method according to claim 1, further comprising before step a the steps of:

i—

detecting the presence of at least one battery cell;

ii—

when the detection of the presence of at least one battery cell of step i fails, reporting an error condition and terminating the charging of the power supply.

10. A method according to claim 1, further comprising before step a the steps of:

i—

measuring the voltage of each battery cell group;

ii—

when the measured voltage of at least one battery cell group of step i meets one condition selected from a group consisting of the voltage of a battery cell group being below a fourth threshold and the voltage of a battery cell group exceeding a fifth threshold, reporting an error condition and terminating the charging of the power supply.

11. A method according to claim 10, wherein the fourth threshold is set to 1V.

12. A method according to claim 10, wherein the fifth threshold is set to 4.235V.

13. A method according to claim 1, further comprising before step a the steps of:

i—

measuring the temperature of the battery cells;

ii—

when the measured temperature of step i meets one condition selected from a group consisting of the temperature being below a sixth threshold and the temperature exceeding a seventh threshold, reporting an error condition and terminating the charging of the power supply.

14. A method according to claim 13, wherein the sixth threshold is set to 0°

C.

15. A method according to claim 13, wherein the seventh threshold is set to 45°

C.

16. A method according to claim 1, further comprising before step a the steps of:

i—

measuring the current through each battery cell group;

ii—

when the measured current of at least one battery cell group of step i is below an eight threshold, reporting an error condition and terminating the charging of the power supply.

17. A method according to claim 16, wherein the eighth threshold is set to C/10, C being a current corresponding to a nominal capacity of the battery cells.

18. A method according to claim 1, further comprising before step a the steps of:

i—

measuring the current through all battery cell groups;

ii—

when the measured current through all battery cell groups of step i exceeds a ninth threshold, reporting an error condition and terminating the charging of the power supply.

19. A method according to claim 18, wherein the ninth threshold is set to 0.6C, C being a current corresponding to a nominal capacity of the battery cells.

20. A power supply charger for charging a power supply having a predetermined number of battery cells divided into at least two battery cell groups, the power supply charger comprising:

a power source input configured to be connected to a power source;

at least two power converters connected to the power input and associated with the at least two battery cell groups, respectively, each of the at least two power converters being associated with a switching controller, a current sensing circuit, a voltage sensing circuit and a balancer circuit;

each of the at least two power converters being provided with terminals configured to be connectable to the battery cell groups;

a micro-controller operatively connected to the switching controllers, current sensing circuits, voltage sensing circuits and balancer circuits, the micro-controller being so configured as to;

a—

for each battery cell group, activate the switching controllers to apply a voltage from the power converters across the battery cell group until one condition selected from the group consisting of the voltage sensing circuit of a battery cell group sensing that the voltage exceeds a first threshold and the current sensing circuit of a battery cell group sensing that the current has dropped below a second threshold, is met;

b—

activate the voltage sensing circuits to verify that each of the predetermined number of battery cells has a similar voltage;

c—

when the verification of the voltage of the battery cells in step b determines that at least one battery cell has a voltage departing from the voltage of the other battery cells by more than a predetermine value, activate the balancer circuits to decrease the voltage of the other cells and return to step a.

21. A power supply charger according to claim 20, wherein the first threshold is set to 4.2V.

22. A power supply charger according to claim 20, wherein the second threshold is set to C/10, C being a current corresponding to a nominal capacity of the battery cells.

23. A power supply charger according to claim 20, the micro-controller being further so configured as to:

d—

for each battery cell group, activate the switching controller to apply a voltage from the power converter across the battery cell group until the current sensing circuit of the battery cell group senses that the current has dropped below a third threshold and stays below the third threshold for a predetermined period of time.

24. A power supply charger according to claim 23, wherein the third threshold is set to C/10, C being a current corresponding to a nominal capacity of the battery cells.

25. A power supply charger according to claim 23, wherein the predetermined period of time is set to 10 minutes.

26. A power supply charger according to claim 20, wherein step c is repeated up to a predetermined maximum number of times.

27. A power supply charger according to claim 26, wherein the predetermined maximum number of times is 3.

28. A power supply charger according to claim 20, further comprising a user interface for operating the apparatus and reporting a status of the apparatus to the user, the user interface being operatively connected to the micro-controller.

29. A power supply charger according to claim 28, the micro-controller being further so configured as to:

i—

detect the presence of at least one battery cell;

ii—

when the detection of the presence of at least one battery cell of step i fails, report an error condition through the user interface and terminate the charging of the power supply.

30. A power supply charger according to claim 28, the micro-controller being further so configured as to:

i—

activate the voltage measuring circuits to measure the voltage of each battery cell group;

ii—

when the measured voltage of at least one battery cell group of step i meets one condition selected from a group consisting of the voltage of a battery cell group being below a fourth threshold and the voltage of a battery cell group exceeding a fifth threshold, report an error condition through the user interface and terminate the charging of the power supply.

31. A power supply charger according to claim 30, wherein the fourth threshold is set to 1 V.

32. A power supply charger according to claim 30, wherein the fifth threshold is set to 4.235V.

33. A power supply charger according to claim 28, further comprising a temperature sensor operatively connected to the micro-controller, the micro-controller being further so configured as to:

i—

activate the temperature sensor to measure the temperature of the power supply charger;

ii—

when the measured temperature of step i meets one condition selected from a group consisting of the temperature being below a sixth threshold and the temperature exceeding a seventh threshold, report an error condition through the user interface and terminate the charging of the power supply.

34. A power supply charger according to claim 33, wherein the sixth threshold is set to 0°

C.

35. A power supply charger according to claim 33, wherein the seventh threshold is set to 45°

C.

36. A power supply charger according to claim 28, the micro-controller being further so configured as to:

i—

activate the current sensing circuits to measure the current of each battery cell group;

ii—

when the measured current of at least one battery cell group of step i is below an eight threshold, report an error condition through the user interface and terminate the charging of the power supply.

37. A power supply charger according to claim 36, wherein the eighth threshold is set to C/10, C being a current corresponding to a nominal capacity of the battery cells.

38. A power supply charger according to claim 28, the micro-controller being further so configured as to:

i—

activate the current sensing circuits to measure the current through all battery cell groups;

ii—

when the measured current through all battery cell groups of step i exceeds a ninth threshold, report an error condition through the user interface and terminate the charging of the power supply.

39. A power supply charger according to claim 38, wherein the ninth threshold is set to 0.6C, C being a current corresponding to a nominal capacity of the battery cells.

40. A power supply charger according to claim 20, further comprising an in-rush limiter connected between the power source input and the at least two power converters.

41. A power supply charger according to claim 20, further comprising a fan connected to the power source input for reducing the temperature of the power supply charger.

42. A power supply charger according to claim 41, wherein the fan is operatively connected to the micro-controller.