Charging apparatus and charging system

• US 5,818,202 A
• Filed: 03/28/1997
• Issued: 10/06/1998
• Est. Priority Date: 06/16/1995
• Status: Expired due to Fees

• Current Assignee: ZIP Charge Corporation
• Original Assignee: ZIP Charge Corporation
• Inventors: Simmonds, Neil, Miyamoto, Isamu
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US08/793,467
• Time in Patent Office: 557 Days
• Field of Search: 230/20, 230/21, 230/22, 230/23, 230/24, 230/30, 230/31, 230/32, 230/39, 230/40, 230/125, 230/120, 230/138, 230/141, 230/145, 230/152, 230/155, 230/159, 230/160, 230/162, 230/133
• US Class Current: 320/125
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• 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

Abstract

A high-speed secondary cell charging system is provided which accurately measures the amount of time to achieve a full-charge condition in a secondary cell. In this system, when charging a secondary cell while detecting a charging characteristic of the secondary cell, charging is performed of the secondary cell using a prescribed amount of charging current. Then, when a prescribed condition with regard to the secondary cell is detected, the secondary cell is charged once again, this time with a current that is smaller than the previous charging current. When a condition indicating the completion of the charging of the secondary cell is detected, the charging is stopped. If this condition is not detected, a yet smaller charging current is set and the charging of the secondary cell is performed once again, the above operations being repeated until a condition which indicates that the charging of the secondary cell is complete is detected.

Claims

1. A charging system in which a charging characteristic of a secondary cell is detected while charging said secondary cell, comprising executing of charging of said secondary cell by using a current of a first prescribed amount, and wherein in the case in which a pre-established condition with regard to said secondary cell is detected, subsequent charging of the secondary cell using a second prescribed amount of current which is smaller than said first prescribed amount of current, after which when said pre-established condition with regard to said secondary cell is detected, charging of the secondary cell is performed yet again, using a third prescribed amount of current which is smaller than said second prescribed amount of current, charging operations being repeated until said secondary cell achieves a condition in which the charging is substantially completed, and further wherein a waiting time period is inserted between each of said operations.

3. A charging system according to either claim 1 or claim 2, wherein said secondary cell which is formed either from a single cell or from a plurality of cells in combination.

7. A charging system according to any one of claims 1, 2, 4, 5, or 6, in which a secondary cell is charged by using a current of a prescribed amount, said charging system having a step whereby when a pre-established condition with regard to said secondary cell is detected, said charging is temporarily interrupted, and said secondary cell is then charged with an amount of current that is smaller than the previous prescribed amount of current, said step being repeated, the amount of time from the start of said charging by using said prescribed amount of current until said charging is stopped being measured, and if a prescribed amount of time elapsed before said charging operation is stopped, said charging operation is stopped at that point in time.

16. A charging system according to claim 3, wherein in the case in which said secondary cell comprises a plurality of cells in combination, each of said plurality of cells has the same nominal capacity and at least one of said plurality of cells has a residual capacity and discharging characteristics that differ from the other cells of said plurality of cells.

2. A charging system in which a charging characteristic of a secondary cell is detected while charging said secondary cell, comprising:

a first time period, during which said secondary cell is charged using a first prescribed amount of current;

a second time period, during which, in the case of detection of a pre-established condition in said secondary cell during the first time period, said secondary cell is charged again with a second prescribed amount of current that is smaller than said first prescribed amount of current;

a third time period during which, in the case of detection of a pre-established condition in the secondary cell during the second time period, the secondary cell is charged again with a third prescribed amount of current that is yet smaller than said second prescribed amount of current; and

a fourth time period, during which the operation of the above-noted third time period is repeated with a prescribed amount of current that is smaller than said previous prescribed amount of current, until the charging of said secondary cell is completed;

wherein a waiting time period is inserted between each of said first through fourth time periods.

4. A charging system in which a charging characteristic of a secondary cell is detected while charging said secondary cell, comprising executing of charging of said secondary cell by using a prescribed amount of current, in said charging system there is included:

a first step which temporarily interrupts said charging operation in the case in which a pre-established condition with regard to said secondary cell is detected, and a second step which, when subsequently charging said secondary cell using a current that has a value that is smaller than said pre-established value, stops said charging operation in the case in which the above-noted pre-established condition with regard to said secondary cell is detected, this second step being repeated as necessary, and when the total number of said stopping of charging operations, including stopping of charging operations in said first step and said second step reaches a pre-established number of times (M), said secondary cell is treated as having substantially reached the full-charge condition, and said charging operation is stopped.

5. A charging system according to claim 4, wherein said total number of stopping of charging operations (M) is an integer which is greater than 1.

6. A charging system in which a charging characteristic of a secondary cell is detected while charging said secondary cell, comprising executing of charging of said secondary cell by using a prescribed amount of current, in said charging step there is included:

a first step which temporarily interrupts said charging operation in the case in which a pre-established condition with regard to said secondary cell is detected, and a second step which, when subsequently charging said secondary cell using a current that has a value that is smaller than said pre-established value, stops said charging operation in the case in which the above-noted pre-established condition with regard to said secondary cell is detected, this second step being repeated as necessary, and when the amount of charging current falls below a pre-established amount of current, said secondary cell is treated as having substantially reached the full-charge condition, and said charging operation is stopped.

8. A secondary cell charging apparatus comprising:

a charging terminal for charging a secondary cell;

a charging characteristic detection means which detects a charging characteristic of said secondary cell;

a current-adjusting means which is connected to said charging terminal and also connected to a prescribed current source; and

a control means which is connected to both said detection means and said current-adjusting means, and which, in response to a signal output from said detection means indicating a pre-established condition with regard to said secondary cell, performs control of said current-adjusting means so as to either stop the current supplied to said charging terminal, or to change the amount of current supplied to said charging terminal, said control means having a function which, when changing the amount of charging current supplied to said charging terminal in response to a charging characteristic detection signal from said detection means, sets a value of the amount of charging current to a prescribed value that is smaller than the amount of charging current used the previous time when charging and repeats said control function upon receiving an indication from said detection means that said same pre-established condition has again been detected.

9. A secondary cell charging apparatus according to claim 8, wherein said control means further comprises a clock means and a timer means.

10. A secondary cell charging apparatus according to either claim 8 claim 9, wherein said charging characteristic detection means includes a means for detecting at least one item selected from the group of secondary cell output voltage, secondary cell surface temperature, and charging current.

11. A secondary cell charging apparatus according to claim 9, wherein said timer means inserts a waiting time period between the time at which the charging operation using a prescribed amount of charging current is stopped and a time that a charging operation using an amount of charging current that is smaller than said prescribed amount of charging current is started.

12. A secondary cell charging apparatus according to claim 9, wherein said timer means controls the elapsed time after the start of a charging operation using a prescribed amount of charging current.

13. A secondary cell charging apparatus according to any one of claims 8, 9, 11, or 12, wherein said prescribed current source comprises a plurality of separate power supplies.

14. A secondary cell charging apparatus according to claim 8, wherein said prescribed current source comprises a programmable power supply.

15. A secondary cell charging apparatus according to any one of claim 8, 9, 11, 12 or 14, wherein said current source comprises a single fixed power supply which, by means of pulse current duty cycle control, controls the amount of charging current.

17. A secondary cell activation system which, in charging a secondary cell while detecting a charging characteristic of said secondary cell, comprises:

a step which measures an output voltage of said secondary cell;

a step which, in the case in which the battery voltage of said secondary cell is below a prescribed voltage, sets an inactivated flag, and then starts charging with a prescribed amount of current;

a step which, in the case in which a prescribed condition regarding said secondary cell is detected, stops said charging operation;

a step which, after said charging operation is stopped, makes a judgment as to whether or not said inactivated flag is set, and which if said inactivated flag is set, makes a judgment as to whether or not a prescribed proportion of the amount of charging time required has elapsed;

a step which, in the case in which more than said prescribed proportion of the amount of charging time required has elapsed, makes a judgment as to whether or not the amount of charge of said secondary cell is below a prescribed amount of charge;

a step which, in the case in which either said prescribed proportion of the amount of charging time required has not elapsed or the amount of charge of said secondary cell is below a prescribed amount of charge, sets a prescribed amount of added charging time;

a step which sets the amount of charging current to be used in said added charging time period to a prescribed value of charging current that is smaller than the amount of charging current that had been used in said charging operation and which starts charging said secondary cell; and

a step which, when said amount of added charging time has elapsed, stops said charging operation.

18. An amount of charge measurement system for a secondary cell being charged while a charging characteristic is detected, in which when measuring the battery voltage of said secondary cell and determining the amount of charging thereof, charging of said secondary cell is performed using a prescribed amount of charging current, the supply of said charging current being stopped each prescribed interval of time, at which point in time the battery voltage of said secondary cell is measured and an asymptote value of the battery voltage thereof is predicted, the amount of charge of said secondary cell being determined based on said predicted battery voltage asymptote value.

19. A secondary cell charging apparatus comprising:

a charging terminal for charging a secondary cell;

a charging characteristic detection means which detects a charging characteristic of said secondary cell;

a current-adjusting means which is connected to said charging terminal and also connected to a prescribed current source;

a control means which is connected to both said detection means and said current-adjusting means, and which, in response to a signal output from said detection means indicating a pre-established condition with regard to said secondary cell, performs control of said current-adjusting means so as to either stop the current supplied to said charging terminal, or to change the amount of current supplied to said charging terminal, said control means having a function which, when changing the amount of charging current supplied to said charging terminal in response to a charging characteristic detection signal from said detection means, sets a value of the amount of charging current to a prescribed value that is smaller than the amount of charging current used the previous time when charging; and

a clock means and a timer means, wherein said timer means inserts a waiting time period between the time at which the charging operation using a prescribed amount of charging current is stopped and a time that a charging operation using an amount of charging current that is smaller than said prescribed amount of charging current is started.

20. A secondary cell charging apparatus comprising:

a charging terminal for charging a secondary cell;

a charging characteristic detection means which detects a charging characteristic of said secondary cell;

a current-adjusting means which is connected to said charging terminal and also connected to a prescribed current source, wherein said prescribed current source comprises a plurality of separate power supplies; and

a control means which is connected to both said detection means and said current-adjusting means, and which, in response to a signal output from said detection means indicating a pre-established condition with regard to said secondary cell, performs control of said current-adjusting means so as to either stop the current supplied to said charging terminal, or to change the amount of current supplied to said charging terminal, said control means having a function which, when changing the amount of charging current supplied to said charging terminal in response to a charging characteristic detection signal from said detection means, sets a value of the amount of charging current to a prescribed value that is smaller than the amount of charging current used the previous time when charging.