Rapidly charging a battery without overcharging

• US 6,111,389 A
• Filed: 06/18/1998
• Issued: 08/29/2000
• Est. Priority Date: 06/18/1998
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Nall, David C., Spinelli, Claudio, Muth, Edwin A., Aranovich, Gene
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/099,253
• Time in Patent Office: 803 Days
• Field of Search: 320/125, 320/144, 320/150, 320/152, 320/153, 320/155, 320/157, 320/162, 320/163, 320/160
• US Class Current: 320/150
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

In the rapid charging of a Nickel Cadmium (NiCad) battery, the rapid charging is terminated and trickle charging is initiated when any of three conditions is satisfied: a first condition determined by comparing a sensed instantaneous battery voltage with a target voltage; a second condition which is determined by comparing the instantaneous battery temperature with minimum and maximum values; and a third condition determined by comparing an elapsed time of rapid charging with a maximum value. Because battery voltage versus rapid charging time is a function of ambient temperature, the target voltage is determined from an initial measurement of battery temperature, which is assumed to equal the ambient temperature. The target voltage, which is approximately a linearly declining function of ambient temperature, is determined by reading a stored lookup table using the sensed temperature as an index or address.

Claims

1. A battery charging control device comprising:

means for determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

means for first comparing a sensed battery voltage with the determined target voltage and based on the result of the first comparing, detecting the occurrence of a first condition;

means for terminating the rapid charging in response to the detection of said first condition;

means for second comparing a sensed battery temperature with a predetermined maximum temperature and based on the result of the second comparing, detecting the occurrence of a second condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first and said second conditions; and

means for third comparing a sensed battery temperature with a predetermined minimum temperature and based on the result of the third comparing, detecting the occurrence of a third condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first, second, and third conditions.

2. A battery charging control device comprising:

means for determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

means for first comparing a sensed battery voltage with the determined target voltage and based on the result of the first comparing, detecting the occurrence of a first condition;

means for terminating the rapid charging in response to the detection of said first condition; and

means for second comparing an elapsed time of charging with a predetermined maximum time and based on the result of the second comparing, detecting the occurrence of a second condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first and second conditions.

3. A battery charging control device comprising:

means for determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

means for first comparing a sensed battery voltage with the determined target voltage and based on the result of the first comparing, detecting the occurrence of a first condition;

means for terminating the rapid charging in response to the detection of said first condition;

means for second comparing a sensed battery temperature with a predetermined maximum temperature and based on the result of the second comparing, detecting the occurrence of a second condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first and said second conditions; and

means for third comparing an elapsed time of charging with a predetermined maximum time and based on the result of the third comparing, detecting the occurrence of a third condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first, second, and third conditions.

4. A battery charging control method comprising:

first determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

first comparing a sensed battery voltage of a battery undergoing rapid charging with the determined target voltage;

second determining whether or not to terminate the rapid charging utilizing the result of said first comparing;

second comparing the sensed battery temperature with a predetermined maximum temperature, wherein said second determining also utilizes the result of said second comparing; and

third comparing the sensed battery temperature with a predetermined maximum temperature;

wherein said second determining also utilizes the result of said third comparing.

5. A battery charging control method comprising:

first determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

first comparing a sensed battery voltage of a battery undergoing rapid charging with the determined target voltage;

second determining whether or not to terminate the rapid charging utilizing the result of said first comparing; and

second comparing an elapsed time of rapid charging with a predetermined maximum time, wherein said second determining also utilizes the result of said second comparing.

6. A battery charging control method comprising:

first determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

first comparing a sensed battery voltage of a battery undergoing rapid charging with the determined target voltage;

second determining whether or not to terminate the rapid charging utilizing the result of said first comparing;

second comparing the sensed battery temperature with a predetermined minimum temperature, wherein said second determining also utilizes the result of said second comparing; and

third comparing an elapsed time of rapid charging with a predetermined maximum time, and wherein said second determining also uses the result of said third comparing.

7. A battery charging control method comprising:

first determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

first comparing a sensed battery voltage of a battery undergoing rapid charging with the determined target voltage;

second determining whether or not to terminate the rapid charging utilizing the result of said first comparing;

second comparing the sensed battery temperature with a predetermined temperature, wherein said second determining also utilizes the result of said second comparing; and

third comparing an elapsed time of rapid charging with a predetermined maximum time, wherein said second determining also utilizes the result of said third comparing.

8. In a method for rapidly charging a battery, a control method comprising:

determining from both a sensed temperature and a sensed voltage when the battery has reached a target charge state;

terminating the rapid charging in response to the result of said determining; and

wherein said determining when the battery has reached a target charge state includes reading a target voltage from a lookup table using the sensed temperature as an index, and comparing the sensed battery voltage with the target voltage.

10. The method of claim 8 wherein:

said determining when the battery has reached a target charge state also takes into account whether an elapsed time of charging is less than a predetermined maximum time.

9. In a method for rapidly charging a battery, a control method comprising:

determining from both a sensed temperature and a sensed voltage when the battery has reached a target charge state;

terminating the rapid charging in response to the result of said determining; and

wherein said determining when the battery has reached a target charge state also takes into account whether an elapsed time of charging is less than a predetermined maximum time.

11. A battery charging control device comprising:

means for determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

means for first comparing a sensed battery voltage measured during a rapid charge of the battery with the determined target voltage and based on the result of the first comparing, detecting the occurrence of a first condition;

means for terminating the rapid charging in response to the detection of said first condition; and

means for second comparing, a sensed battery temperature with a predetermined maximum temperature and based on the result of the second comparing, detecting the occurrence of a second condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first and said second conditions.

12. A battery charging control device comprising:

means for determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

means for first comparing a sensed battery voltage measured during a rapid charge of the battery with the determined target voltage and based on the result of the first comparing, detecting the occurrence of a first condition;

means for terminating the rapid charging in response to the detection of said first condition; and

means for second comparing a sensed battery temperature with a predetermined minimum temperature and based on the result of the second comparing, detecting the occurrence of a second condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first and said second conditions.

13. A battery charging control method comprising:

first determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

first comparing a sensed battery voltage of a battery measured during a rapid charge of the battery with the determined target voltage;

second determining whether or not to terminate the rapid charging utilizing the result of said first comparing; and

second comparing the sensed battery temperature with a predetermined maximum temperature, wherein said second determining also utilizes the result of said second comparing.

14. A battery charging control method comprising:

first determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

first comparing a sensed battery voltage of a battery measured during a rapid charge of the battery with the determined target voltage;

second determining whether or not to terminate the rapid charging utilizing the result of said first comparing; and

second comparing the sensed battery temperature with a predetermined minimum temperature, wherein said second determining also utilizes the result of said second comparing.

15. A battery charging control device comprising:

a voltage measurement device adapted for measuring a sensed battery voltage measured during a rapid charge of the battery;

a temperature measurement element adapted for measuring a sensed battery temperature;

a processing unit adapted to determine a target voltage as a function of the sensed battery temperature, compare the sensed battery voltage with the determined target voltage, and detect the occurrence of a first condition based on the sensed battery voltage equaling or exceeding the determined target;

a switch control unit communicatively connected to the processing unit and adapted for controlling the rapid charge of the battery based on the detection of the occurrence of the first condition by the processing unit;

wherein the processing unit is further adapted to compare the sensed battery temperature with a predetermined maximum temperature and detect the occurrence of a second condition based on the sensed battery temperature equaling or exceeding the predetermined maximum temperature; and

wherein the switch control unit is further adapted for controlling the rapid charge of the battery based on the detection of the occurrence of the second condition by the processing unit.

16. A battery charging control device comprising:

a voltage measurement device adapted for measuring a sensed battery voltage measured during a rapid charge of the battery;

a temperature measurement element adapted for measuring a sensed battery temperature;

a processing unit adapted to determine a target voltage as a function of the sensed battery temperature, compare the sensed battery voltage with the determined target voltage, and detect the occurrence of a first condition based on the sensed battery voltage equaling or exceeding the determined target;

a switch control unit communicatively connected to the processing unit and adapted for controlling the rapid charge of the battery based on the detection of the occurrence of the first condition by the processing unit;

wherein the processing unit is further adapted to compare the sensed battery temperature with a predetermined minimum temperature and detect the occurrence of a second condition based on the sensed battery temperature being less than the predetermined minimum temperature; and

wherein the switch control unit is further adapted for controlling the rapid charge of the battery based on the detection of the occurrence of the second condition by the processing unit.

17. A battery charging control device comprising:

a voltage measurement device adapted for measuring a sensed battery voltage measured during a rapid charge of the battery;

a temperature measurement element adapted for measuring a sensed battery temperature;

a processing unit adapted to determine a target voltage as a function of the sensed battery temperature, compare the sensed battery voltage with the determined target voltage, and detect the occurrence of a first condition based on the sensed battery voltage equaling or exceeding the determined target;

a switch control unit communicatively connected to the processing unit and adapted for controlling the rapid charge of the battery based on the detection of the occurrence of the first condition by the processing unit;

wherein the processing unit is further adapted to compare an elapsed time of charging with a predetermined maximum time and detect the occurrence of a second condition based on the elapsed time of charging equaling or exceeding the predetermined maximum time; and

wherein the switch control unit is further adapted for controlling the rapid charge of the battery based on the detection of the occurrence of the second condition by the processing unit.

18. A battery charging control device comprising:

means for determining a target voltage as a function of a sensed battery temperature or a sensed ambient temperature;

means for first comparing a sensed battery voltage with the determined target voltage and based on the result of the first comparing, detecting the occurrence of a first condition;

means for terminating the rapid charging in response to the detection of said first condition;

means for second comparing a sensed battery temperature with a predetermined minimum temperature and based on the result of the second comparing, detecting the occurrence of a second condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first and said second conditions; and

means for a third comparing an elapsed time of charging with a predetermined maximum time and based on the result of the third comparing, detecting the occurrence of a third condition;

wherein said terminating means is for terminating the rapid charging in response to the detection of occurrence of any of the first, second, and third conditions.