Refreshing charge control method and apparatus to extend the life of batteries

• US 6,011,380 A
• Filed: 03/31/1999
• Issued: 01/04/2000
• Est. Priority Date: 03/31/1999
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Paryani, Anil, Sando, Yasuyuki
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/282,263
• Time in Patent Office: 279 Days
• Field of Search: 320/124, 320/125, 320/128, 320/130, 320/132, 320/135, 320/137, 320/150, 320/160, 320/DIG. 21
• US Class Current: 320/132
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/26 by cooling
• CPC Class Codes: B60L 58/27 by heating
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method and apparatus for charging a battery which is operable to normally charge the battery at a first state of charge setting, to determine when the battery has been undercharged a predetermined number of times, and to charge the battery at a second state of charge setting after the battery is undercharged the predetermined number of times. The second state of charge setting is greater than the first state of charge setting. The method includes determining when the state of charge of the battery is below a predetermined level, charging the battery at the first state of charge setting, calculating a number of charging times when the battery was charged below the predetermined level after the last time the battery was charged at the predetermined level, and charging the battery with a second state of second charge setting when the calculated number of charging times equals a predetermined number. The apparatus includes a sensor for sensing the state of charge of the battery, a counter for counting the number of charging times that the battery was charged below a predetermined level after the last time the battery was charged to the predetermined level, and a charger for applying the second state of charge setting when the number of charging times counted by the counter equals the predetermined number.

Claims

1. A method for charging a battery with at least one of a first state of charge setting and a second state of charge setting, said second state of charge setting being greater than said first state of charge setting, said method comprising the steps of:

a) determining when the state of charge of said battery is below a predetermined level;

b) calculating a number of charging times that said battery was charged below said predetermined level after the last time said battery was charged at said predetermined level;

c) charging said battery at said first state of charge setting if said calculated number is below a predetermined number; and

,

d) charging said battery at said second state of charge setting when said calculated number is equal to said predetermined number.

2. The method of claim 1, comprising the further steps of:

storing said calculated number of charging times when said battery was charged below said predetermined level;

resetting said calculated number of charging times after said battery is charged at the predetermined level.

3. The method of claim 1, wherein said predetermined number is between about one and five.

4. The method of claim 1, wherein said first state of charge setting is equal to about 105 percent of a fully charged battery.

5. The method of claim 1, wherein said second state of charge setting is between about 110 and 120 percent of a fully charged battery.

6. The method of claim 1, wherein step b includes the steps of:

detecting when said battery has been discharged;

calculating said number of charging times when said battery was charged below said predetermined level and when said battery has been detected to be discharged.

7. A system for charging a battery, said battery being charged with at least one of a first state of charge setting and a second state of charge setting, said second state of charge setting being greater than said first state of charge setting, said system comprising:

means for charging said battery at said first state of charge setting;

means for sensing the state of charge of said battery;

means for determining when the state of charge of said battery is below a predetermined level;

means for calculating a number of charging times when said battery was charged below said predetermined level after the last time said battery was charged to said predetermined level; and

means for charging said battery at the second state of charge setting when said number of charging times calculated by said calculating means is at the predetermined number.

8. The system of claim 7, further comprising:

memory means for storing said number of charging times when said battery was charged below said predetermined level; and

means for resetting said number of charging times after said battery is charged to a predetermined level.

9. The system of claim 7, wherein said predetermined number of charging times is between about one and five.

10. The system of claim 7, wherein said first state of charge setting is equal to about 105 percent of a fully charged battery.

11. The system of claim 7, wherein said second state of charge setting is between about 110 percent and 120 percent of a fully charged battery.

12. The system of claim 7, wherein said battery is a Nickel-Metal Hydride battery.

13. The system of claim 7, wherein said calculating means includes means for detecting that the battery has been discharged.

14. A method for charging a battery with at least one of a first state of charge setting and a second state of charge setting, said second state of charge setting being greater than said first state of charge setting, said method comprising the steps of:

a) determining when the state of charge of said battery is below a predetermined level;

b) calculating a number of charging times when said battery was charged below said predetermined level after the last time said battery was charged at said predetermined level;

c) charging said battery at said first state of charge setting if said calculated number of charging times is below a predetermined number;

d) charging said battery at said second state of charge setting when said calculated number of charging times is equal to said predetermined number;

e) determining if said battery is in a high-temperature condition; and

,

f) charging said battery at said first state of charge setting if it is determined that said battery is in said high temperature condition;

g) charging said battery at said first or second state of charge setting determined in steps (c) and (d) if said battery is not in said high-temperature condition.

15. The method of claim 14, comprising the further steps of:

h) storing said calculated number; and

,

i) if said battery is not in said high temperature condition and said battery is charged at the predetermined level, decrementing said calculated number.

16. The method of claim 14, comprising the further steps of:

h) storing said calculated number;

i) if said battery is in said high-temperature condition, incrementing said calculated number.

17. The method of claim 16, wherein said calculated number is incremented regardless of whether the battery is charged at the predetermined level.

18. The method of claim 14, wherein said predetermined number is between about one and five.

19. The method of claim 15, wherein said predetermined number is between about one and five.

20. The method of claim 16, wherein said predetermined number is between about one and five.

21. The method of claim 14, wherein said first state of charge setting is equal to about 105 percent of a fully charged battery.

22. The method of claim 15, wherein said first state of charge setting is equal to about 105 percent of a fully charged battery.

23. The method of claim 16, wherein said first state of charge setting is equal to about 105 percent of a fully charged battery.

24. The method of claim 14, wherein said second state of charge setting is between about 110 and 120 percent of a fully charged battery.

25. The method of claim 15, wherein said second state of charge setting is between about 110 and 120 percent of a fully charged battery.

26. The method of claim 16, wherein said second state of charge setting is between about 110 and 120 percent of a fully charged battery.