Charging equipment for secondary battery

• US 7,075,269 B2
• Filed: 06/09/2004
• Issued: 07/11/2006
• Est. Priority Date: 02/25/2004
• Status: Active Grant

• Current Assignee: Goiku Battery Co., Ltd.
• Original Assignee: Techno Core International Co., Ltd.
• Inventors: Takaoka, Hiromi, Fujiwara, Takamichi, Osabe, Yasuo
• Primary Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US10/517,820
• Publication Number:
  US 20050231163A1
• Time in Patent Office: 762 Days
• Field of Search: 320/107
• US Class Current: 320/107
• CPC Class Codes: H02J 7/00041 in response to measured battery parameters, e.g. voltage, current or temperature profile
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process

Abstract

An object of the present invention is to provide a charging equipment for a secondary battery that can charge any secondary battery, regardless of its kind, size and the like, until its charging rate comes to approximately 100%. The charging equipment comprises: a voltage increment device for incrementing a check voltage by a preset pitch of voltage from a lowest check voltage lower than a rated equilibrium voltage at full charge; a switch for switching applied voltage to the secondary battery to the special charging voltage or the check voltage supplied; a first judging means for judging whether an electric current detected by a current detection part is smaller than or as large as a preset standard electric current for judging; and a second judging means for judging whether the time required for the period from the last affirmative judgment to the present affirmative judgment is larger than two times as large as the time required for the period from the before-last affirmative judgment to the last affirmative judgment.

Claims

1. A charger for a secondary battery, comprising:

a voltage increment means for incrementing a check voltage by a preset pitch of voltage, the incrementing being from a lowest check voltage lower than a rated equilibrium voltage at full charge of any secondary battery of all kinds to be charged;

a charge voltage supply means for supplying special charging voltage, wherein the special charging voltage is higher than the rated equilibrium voltage at full charge of any secondary battery of all kinds to be charged, but does not enter an irreversible chemical reaction region;

a switch means for switching voltage applied to the secondary battery between a voltage selected from the group consisting of the special charging voltages supplied by the charge voltage supply means, and the check voltage supplied by the voltage increment means;

a current detection means for detecting an electric current flowing through the secondary battery during application of the check voltage to the secondary battery;

a first judging means for judging whether the electric current detected by the current detection means is smaller than or as large as a preset standard electric current for judging; and

a second judging means for judging whether a time required for a period from the last affirmative judgment judged by the first judging means to the present affirmative judgment judged by the first judging means is larger than r times as large as a time required for a period from the before-last affirmative judgment judged by the first judging means to the last affirmative judgment judged by the first judging means, where r is a real number not smaller than 1,

wherein charging of the secondary battery is controlled according to the following;

wherein in the first step the lowest check voltage is applied to the secondary battery for a short time, and the current detection means detects electric current flowing through the secondary battery during the short time;

wherein in the second step the first judging means judges the detected electric current so as to execute a command selected from the group consisting of;

passing to the third step when the electric current is larger than the standard electric current for judging, and

jumping to the fourth step when the electric current is smaller than or as large as the standard electric current for judging;

wherein in the third step the switch means switches the applied voltage to the special charging voltage, the special charging voltage being applied to the secondary battery for a predetermined time, and then the switch means switches the applied voltage to the lowest check voltage, and a step returns to the first step;

wherein in the fourth step the voltage increment means sets a renewed check voltage made by the present check voltage plus the pitch of voltage;

wherein in the fifth step the switch means switches the applied voltage to the special charging voltage, the special charging voltage being applied to the secondary battery for a predetermined time, and then the switch means switches the applied voltage to the renewed check voltage, the renewed check voltage is applied to the secondary battery for a short time, wherein the current detection means detects electric current flowing through the secondary battery during the application of the renewed check voltage to the secondary battery;

wherein in the sixth step the first judging means judges the detected electric current so as to execute a command selected from the group consisting of;

returning to the fifth step when the electric current is larger than the standard electric current for judging, and

passing to the seventh step when the electric current is smaller than or as large as the standard electric current for judging; and

wherein in the seventh step the second judging means judges the time required for the period from the last affirmative judgment judged by the first judging means to the present affirmative judgment judged by the first judging means so as to execute a command selected from the group consisting of;

returning to the fourth step when the time required for the period from the last affirmative judgment judged by the first judging means to the present affirmative judgment judged by the first judging means is not larger than r times as large as the time required for the period from the before-last affirmative judgment judged by the first judging means to the last affirmative judgment judged by the first judging means, and

outputting a signal to stop charging when the time required for the period from the last affirmative judgment judged by the first judging means to the present affirmative judgment judged by the first judging means is larger than r times as large as the time required for the period from the before-last affirmative judgment judged by the first judging means to the last affirmative judgment judged by the first judging means.

2. The charger for a secondary battery according to claim 1, wherein, when the signal to stop charging is outputted at the seventh step, the switch means switches the applied voltage to the special charging voltage, the special charging voltage being applied to the secondary battery for a second predetermined time, and then charge of the secondary battery is finished.

3. The charger for a secondary battery according to claim 1, wherein the required time is measured by counting the number of switchings of the applied voltage to the check voltage by the switch means.

4. The charger for a secondary battery according to any of claims claim 1, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal, wherein w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, wherein n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n.

a supremum and infimum voltage setting circuit for inverting the maximum and the minimum amplitude of the pulse wave outputted from an output terminal to each other, and setting the maximum amplitude of the inverted pulse wave as a supremum voltage and the minimum amplitude of the inverted pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage minus the just averaged voltage,

wherein the valuable variable c in the microcomputer is incremented, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

5. The charger for a secondary battery according to claim 1, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal, wherein w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, wherein n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for setting the maximum amplitude of the pulse wave outputted from an output terminal as a supremum voltage and the minimum amplitude of the pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage plus the just averaged voltage,

wherein the variable c in the microcomputer is incremented, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

6. The charger for a secondary battery according to claim 1, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal on the premise that w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for inverting the maximum and the minimum amplitude of the pulse wave outputted from an output terminal to each other, and setting the maximum amplitude of the inverted pulse wave as a supremum voltage and the minimum amplitude of the inverted pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage plus the just averaged voltage,

wherein the variable c in the microcomputer is decreased, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

7. The charger for a secondary battery according to claim 1, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal on the premise that w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for setting the maximum amplitude of the pulse wave outputted from an output terminal as a supremum voltage and the minimum amplitude of the pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage minus the just averaged voltage,

wherein the variable c in the microcomputer is decreased, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

8. The charger for a secondary battery according to claim 2, wherein the required time is measured by counting the number of switchings of the applied voltage to the check voltage by the switch means.

9. The charger for a secondary battery according to claim 2, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal, wherein w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for inverting the maximum and the minimum amplitude of the pulse wave outputted from an output terminal to each other, and setting the maximum amplitude of the inverted pulse wave as a supremum voltage and the minimum of amplitude the inverted pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage minus the just averaged voltage,

wherein the variable c in the microcomputer is incremented, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

10. The charger for a secondary battery according to claim 3, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal, wherein w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, wherein n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for inverting the maximum and the minimum amplitude of the pulse wave outputted from an output terminal to each other, and setting the maximum amplitude of the inverted pulse wave as a supremum voltage and the minimum amplitude of the inverted pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage minus the just averaged voltage,

wherein the variable c in the microcomputer is incremented, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

11. The charger for a secondary battery according to claim 2, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal, wherein w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for setting the maximum amplitude of the pulse wave outputted from an output terminal as a supremum voltage and the minimum amplitude of the pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage plus the just averaged voltage,

wherein the variable c in the microcomputer is incremented, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

12. The charger for a secondary battery according to claim 3, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal wherein w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2 and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for setting the maximum amplitude of the pulse wave outputted from an output terminal as a supremum voltage and the minimum amplitude of the pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage plus the just averaged voltage,

wherein the variable c in the microcomputer is incremented, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

13. The charger for a secondary battery according to claim 2, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal on the premise that w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2 and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for inverting the maximum and the minimum amplitude of the pulse wave outputted from an output terminal to each other, and setting the maximum amplitude of the inverted pulse wave as a supremum voltage and the minimum of amplitude of the inverted pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage plus the just averaged voltage,

wherein the variable c in the microcomputer is decreased, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

14. The charger for a secondary battery according to claim 3, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal on the premise that w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2 and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for inverting the maximum and the minimum of amplitude the pulse wave outputted from an output terminal to each other, and setting the maximum amplitude of the inverted pulse wave as a supremum voltage and the minimum of amplitude of the inverted pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage plus the just averaged voltage,

wherein the variable c in the microcomputer is decremented, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

15. The charger for a secondary battery according to claim 2, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal on the premise that w is a time having a length of one of n (n is an integer not smaller than

     2) equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for setting the maximum amplitude of the pulse wave outputted from an output terminal as a supremum voltage and the minimum amplitude of the pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage minus the just averaged voltage,

wherein the variable c in the microcomputer is decreased, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.

16. The charger for a secondary battery according to claim 3, the voltage increment means comprising:

a microcomputer for outputting a pulse wave of pulse width c·

w from one predetermined output terminal on the premise that w is a time having a length of one of n equal divisional parts of one cycle of the pulse wave, where n is an integer not smaller than 2, and c is a variable represented as an integer between 1 and n;

a supremum and infimum voltage setting circuit for setting the maximum amplitude the pulse wave outputted from an output terminal as a supremum voltage and the minimum of amplitude of the pulse wave as an infimum voltage; and

an arithmetic circuit for averaging the voltage of the pulse wave outputted from the supremum and infimum voltage setting circuit, and outputting a value of voltage made by a base voltage minus the just averaged voltage,

wherein the variable c in the microcomputer is decreased, so that the value of voltage outputted from the arithmetic circuit is incremented by the pitch of voltage.