Secondary cell charger and charging method

• US 20040257043A1
• Filed: 07/02/2004
• Published: 12/23/2004
• Est. Priority Date: 05/17/2002
• Status: Active Grant

• Current Assignee: Techno Core International Co., Ltd., The New Industry Research Organization
• Original Assignee: Techno Core International Co., Ltd., The New Industry Research Organization
• Inventors: Nakamura, Osamu, Takaoka, Hiromi, Matsui, Shigetomo, Nishino, Taneo, Iuchi, Yutaka
• Granted Patent: US 7,109,684 B2
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/00716 in response to integrated charge or discharge current
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

An equipment and method for charging a secondary battery are provided to quickly and surely charge a secondary battery (secondary batteries) while preventing the secondary battery (batteries) from overcharging or insufficient charging. Special charging voltage E_s is applied to a secondary battery for a predetermined time, and then the applied voltage is switched to equilibrium voltage E_eq for establishing equilibrium cell potential of the secondary battery in its fully charged condition, wherein the special charging value E_s is larger than the equilibrium value E_eq. Electric current i is detected while application of the equilibrium voltage E_eq. If the detected electric current i is larger than standard electric current J for finishing charging, the above detection and charging are repeated; otherwise, charge of the secondary battery 1 is halted.

Claims

1. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a current detection means for detecting electric current flowing through the secondary battery; and

a charge control device for controlling charge of the secondary battery, the charge control device including

a storage means storing equilibrium voltage and special charging voltage corresponding to the secondary battery to be charged, the equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and the special charging voltage for supplying the secondary battery with charging electric current of peak or almost peak value, wherein the special charging voltage is larger than the equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the secondary battery,

a switching means for switching charging voltage supplied by the voltage supply means between the equilibrium voltage and the special charging voltage, and

a judging means for judging whether electric current detected by the current detection means during application of the equilibrium voltage is larger than a preset standard electric current for finishing charging or not,

wherein the charge control device controls charge of a secondary battery by first to fourth steps;

the first step of applying the special charging voltage to the secondary battery set in the charging equipment for a predetermined time;

the second step of switching charging voltage applied to the secondary battery from the special charging voltage to the equilibrium voltage;

the third step of detecting electric current flowing through the secondary battery by the current detection means while applying the equilibrium voltage to the secondary battery for a short time; and

the fourth step of returning to the first step and repeating the above steps if the judging means judges that the detected electric current is larger than the standard electric current for finishing charging;

otherwise, halting the secondary battery.

2. A charging equipment for a secondary battery according to claim 1,

wherein the storage means of the charge control device previously stores the equilibrium voltages and the special charging voltages for charging various kinds of secondary batteries, and

wherein data of a kind of secondary battery to be charged is inputted to the charge control device so that the equilibrium voltage and the special charging voltage in correspondence to the kind of secondary battery are selected from a table of the storage means so as to charge the kind of secondary battery basing on the selected equilibrium voltage and special charging voltage.

3. A charging equipment for a secondary battery according to claim 1 or 2, further comprising:

a short-circuit means for short-circuiting the secondary battery between its terminals after applying the special charging voltage for the predetermined time and before switching charging voltage to the equilibrium voltage.

4. A charging equipment for a secondary battery according to any of claims 1 to 3, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

5. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a current detection means for detecting electric current flowing through the secondary battery;

a voltage detection means for detecting voltage applied to the secondary battery; and

a charge control device for controlling charge of the secondary battery, the charge control device including

a storage means storing n (n is a natural number larger than

     1) equilibrium voltages and n special charging voltages for charging n kinds of secondary batteries, each of the equilibrium voltages for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and each of the special charging voltages for supplying the secondary battery with charging electric current of peak or almost peak value, wherein each of the special charging voltages is larger than the corresponding equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the corresponding secondary battery;

a switching means for switching charging voltage supplied by the voltage supply means;

a current judging means for judging whether electric current detected by the current detection means during application of charging the equilibrium voltage is larger than a preset standard electric current for finishing charging or not; and

a voltage judging means for judging whether voltage detected by the voltage detection means during application of charging voltage of the predetermined value is larger than the special charging voltage or not,

wherein the charge control device controls charge of a secondary battery by first to eighth steps;

the first step of initializing a counter variable k (k=1,2, . . . ,n) to 1;

the second step of applying the kth smallest voltage of the n special charging voltages to the secondary battery set in the charging equipment for a predetermined time;

the third step to jumping to the sixth step if k is equal to n;

the fourth step of detecting voltage applied to the secondary battery by the voltage detection means while applying the kth smallest special charging voltage to the secondary battery for the predetermined time;

the fifth step of incrementing the rank of k by 1 and returning to the second step if the voltage judging means judges that the detected voltage is larger than the kth smallest special charging voltage;

otherwise, passing to the sixth step;

the sixth step of switching charging voltage applied to the secondary battery to the kth smallest voltage of the n equilibrium voltages;

the seventh step of detecting electric current flowing through the secondary battery by the current detection means while applying the kth smallest equilibrium voltage to the secondary battery for a short time; and

the eighth step of returning to the second step and repeating the above steps if the current judging means judges that the detected electric current is larger than the standard electric current for finishing charging;

otherwise, halting charge of the secondary battery.

6. A charging equipment for a secondary battery according to claim 5, further comprising:

a short-circuit for short-circuiting the secondary battery between its terminals after applying the special charging voltage for the predetermined time and before switching charging voltage to the equilibrium voltage.

7. A charging equipment for a secondary battery according to claim 5 or 6, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

8. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a current detection means for detecting electric current flowing through the secondary battery;

a voltage detection means for detecting voltage applied to the secondary battery; and

a charge control device for controlling charge of the secondary battery, the charge control device including

a storage means storing n (n is a natural number larger than

     1) equilibrium voltages and n special charging voltages for charging n kinds of secondary batteries, each of the equilibrium voltages for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and each of the special charging voltages for supplying the secondary battery with charging electric current of peak or almost peak value, wherein each of the special charging voltages is larger than the corresponding equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the corresponding secondary battery;

a switching means for switching charging voltage supplied by the voltage supply means;

a current judging means for judging whether electric current detected by the current detection means during application of the equilibrium voltage is larger than a preset standard electric current for finishing charging or not, and

a voltage difference judging means for judging whether a difference of voltage detected by the voltage detection means during application of the special charging voltage between a present value and a past value is within a preset range or not,

wherein the charge control device controls charge of a secondary battery by first to eighth steps;

the first step of initializing a counter variable k (k=1,2, . . . ,n) to 1;

the second step of applying the kth smallest voltage of the n special charging voltages to the secondary battery set in the charging equipment for a predetermined time;

the third step of jumping to the sixth step if k is equal to n;

the fourth step of detecting voltage applied to the secondary battery by the voltage detection means while applying the kth smallest special charging voltage to the secondary battery for the predetermined time;

the fifth step of passing to the sixth step if the voltage detection is the first time or the voltage difference judging means judges that the detected voltage difference is within the range;

otherwise, incrementing the rank of k by 1 and returning to the second step;

the sixth step of switching charging voltage applied to the secondary battery from the kth smallest special charging voltage to the kth smallest voltage of the n equilibrium voltages;

the seventh step of detecting electric current flowing through the secondary battery by the current detection means while applying the kth equilibrium voltage to the secondary battery for a short time; and

the eighth step of returning to the second step and repeating the above steps if the current judging means judges that the detected electric current is larger than the standard electric current for finishing charging;

otherwise, halting charge of the secondary battery.

9. A charging equipment for a secondary battery according to claim 8, further comprising:

a short-circuit for short-circuiting the secondary battery between its terminals after applying the special charging voltage for the predetermined time and before switching charging voltage to the equilibrium voltage.

10. A charging equipment for a secondary battery according to claim 8 or 9, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

11. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a voltage detection means for detecting open-circuit voltage of the secondary battery; and

a charge control device for controlling charge of the secondary battery, the charge control device including

a storage means storing special charging voltage for supplying the secondary battery with charging electric current of peak or almost peak value, wherein the special charging voltage is larger than voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition and does not reach a region of voltage causing irreversible chemical reaction in the secondary battery, and

a voltage difference judging means for judging whether a voltage difference between the charging voltage and the open-circuit voltage of the secondary battery is larger than a preset standard value or not,

wherein the charge control device controls charge of a secondary battery by first to third steps;

the first step of applying the special charging voltage to the secondary battery set in the charging equipment for a predetermined time, and then shutting off the charging voltage from the secondary battery;

the second step of detecting the open-circuit voltage of the secondary battery by the voltage detection means, and computing the voltage difference between the charging voltage of the special charging voltage and the open-circuit voltage of the secondary battery; and

the third step of returning to the first step and repeating the above steps if the voltage difference judging means judges that the computed voltage difference is larger than the standard value;

otherwise, halting charge of the secondary battery.

12. A charging equipment for a secondary battery according to claim 11, further comprising:

an informational means for giving information of the time required to charge the secondary battery, the charging rate of the secondary battery, or a charged condition of the secondary battery for deciding whether charge of the secondary battery is finished or not.

13. A charging equipment for a secondary battery according to claim 11 or 12, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

14. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a voltage detection means for detecting open-circuit voltage of the secondary battery; and

a charge control device for controlling charge of the secondary battery, the charge control device including

a storage means storing equilibrium voltage and special charging voltage corresponding to the secondary battery to be charged, the equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and the special charging voltage supplying the secondary battery with charging electric current of peak or almost peak value, wherein the special charging voltage is larger than the equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the secondary battery,

a judging means for judging whether the open-circuit voltage of the secondary battery detected by the voltage detection means is larger than a standard voltage as the equilibrium voltage or not,

wherein the charge control device controls charge of a secondary battery by first to third steps;

the first step of applying the special charging voltage to the secondary battery set in the charging equipment for a predetermined time, and then shutting off the charging voltage from the secondary battery;

the second step of detecting the open-circuit voltage of the secondary battery by the voltage detection means, and computing the voltage difference between the special charging voltage and the open-circuit voltage of the secondary battery; and

the third step of returning to the first step and repeating the above steps if the judging means judges that the detected open-circuit voltage is smaller than the equilibrium voltage as the standard voltage;

otherwise, halting charge of the secondary battery.

15. A charging equipment for a secondary battery according to claim 14, further comprising:

an informational means for giving information of the time required to charge the secondary battery, the charging rate of the secondary battery, or a charged condition of the secondary battery for deciding whether charge of the secondary battery is finished or not.

16. A charging equipment for a secondary battery according to claim 14 or 15, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

17. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying predetermined voltage to the secondary battery;

a current detection means for detecting a value of electric current flowing through the secondary battery during application of the predetermined voltage to the secondary battery; and

a charge time predicting means for estimating a time required to fully charge the secondary battery basing on the detected value of electric current.

18. A charging equipment for a secondary battery according to claim 17, wherein the voltage supply means applies charging voltage, which is larger than the predetermined voltage, to the secondary battery for a predetermined time, and then applied voltage is switched to the predetermined voltage, and the current detection means detects a value of electric current flowing through the secondary battery during application of the special charging voltage.

19. A charging equipment for a secondary battery according to claim 17 or 18, wherein the time required to fully charge the secondary battery is a time for the electric current detected by the current detection means to reach standard electric current for finishing charging, whereby charge of the secondary battery is halted when the detected value of electric current is not larger than the standard electric current for finishing charging.

20. A charging equipment for a secondary battery according to any of claims 17 to 19, wherein the charging equipment halts charge of the secondary battery after the lapse of the time required to fully charge the secondary battery.

21. A charging equipment for a secondary battery according to any of claims 17 to 20, wherein the predetermined voltage is equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition.

22. A charging equipment for a secondary battery according to any of claims 17 to 21, further comprising:

an informational means for giving information of the time required to fully charge the secondary battery, the charging rate of the secondary battery, or a charged condition of the secondary battery for deciding whether charge of the secondary battery is finished or not.

23. A charging equipment for a secondary battery according to any of claims 17 to 22, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

24. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying special charging voltage to the secondary battery;

a current detection means for detecting electric current flowing through the secondary battery during application of the special charging voltage to the secondary battery; and

a charging rate computing means for computing a charging rate of the secondary battery at the moment when the current detection means detects the electric current.

25. A charging equipment for a secondary battery according to claim 24, wherein the voltage supply means applies charging voltage, which is larger than the special charging voltage, to the secondary battery for a predetermined time, and then the charging voltage is switched to the special charging voltage, and the current detection means detects electric current flowing through the secondary battery during application of the special charging voltage.

26. A charging equipment for a secondary battery according to claim 24 or 25, further comprising:

an informational means for giving information of the time required to fully charge the secondary battery, the charging rate of the secondary battery, or a charged condition of the secondary battery for deciding whether charge of the secondary battery is finished or not.

27. A charging equipment for a secondary battery according to any of claims 24 to 26, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

28. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a current detection means for detecting electric current flowing through the secondary battery; and

a charge control device for controlling charge of the secondary battery, the charge control device including

a storage means storing equilibrium voltage and special charging voltage corresponding to the secondary battery to be charged, the equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and the special charging voltage for supplying the secondary battery with charging electric current of peak or almost peak value, wherein the special charging voltage is larger than the equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the secondary battery,

a switching means for switching charging voltage supplied by the voltage supply means between the equilibrium voltage and the special charging voltage, and

a charge time predicting means for estimating a time required to fully charge the secondary battery basing on the detected electric current,

wherein the charge control device controls charge of a secondary battery by first to sixth steps;

the first step of applying the special charging voltage to the secondary battery set in the charging equipment for a predetermined time;

the second step of switching charging voltage applied to the secondary battery from the special charging voltage to the equilibrium voltage;

the third step of detecting electric current flowing through the secondary battery by the current detection means while applying charging the equilibrium voltage to the secondary battery for a short time;

the fourth step of predicting a time required to fully charge the secondary battery by the charge time predicting means basing on the detected electric current;

the fifth step of switching charging voltage applied to the secondary battery from the equilibrium voltage to the special charging voltage; and

the sixth step of halting charge of the secondary battery after the lapse of the time required to fully charge the secondary.

29. A charging equipment for a secondary battery according to claim 28, further comprising:

a short-circuit means for short-circuiting the secondary battery between its terminals after applying the special charging voltage for the predetermined time and before switching charging voltage to the equilibrium voltage.

30. A charging equipment for a secondary battery according to claim 28 or 29, further comprising:

an informational means for giving information of the time required to fully charge the secondary battery, the charging rate of the secondary battery, a charged condition of the secondary battery for deciding whether charge of the secondary battery is finished or not.

31. A charging equipment for a secondary battery according to any of claims 28 to 30, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

32. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a current detection means for detecting electric current flowing through the secondary battery; and

a charge control device for controlling charge of the secondary battery, the charge control device including

a storage means storing equilibrium voltage and special charging voltage corresponding to the secondary battery to be charged, the equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and the special charging voltage for supplying the secondary battery with charging electric current of peak or almost peak value, wherein the special charging voltage is larger than the equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the secondary battery,

a switching means for switching charging voltage supplied by the voltage supply means between the equilibrium voltage and the special charging voltage,

a charging rate computing means for computing a charging rate of the secondary battery at the moment when the current detection means detects the electric current, and

a judging means for judging whether the charging rate computed by the charging rate computing means is larger than a preset standard value or not,

wherein the charge control device controls charge of a secondary battery by first to fifth steps;

the first step of applying the special charging voltage to the secondary battery set in the charging equipment for a predetermined time;

the second step of switching charging voltage applied to the secondary battery from the special charging voltage to the equilibrium voltage;

the third step of detecting electric current flowing through the secondary battery by the current detection means while applying the equilibrium voltage to the secondary battery for a short time;

the fourth step of computing the charging rate of the secondary battery by the charging rate computing means at the moment when the electric current is detected; and

the fifth step of returning to the first step and repeating the above steps if the judging means judges that the computed value of charging rate is not larger than the standard value;

otherwise, halting charge of the secondary battery.

33. A charging equipment for a secondary battery according to claim 32, further comprising:

a short-circuit means for short-circuiting the secondary battery between its terminals after applying the special charging voltage for the predetermined time and before switching charging voltage to the equilibrium voltage.

34. A charging equipment for a secondary battery according to claim 32 or 33, further comprising:

an informational means for giving information of the time required to fully charge the secondary battery, the charging rate of the secondary battery, or a charged condition of the secondary battery for deciding whether charge of the secondary battery is finished or not.

35. A charging equipment for a secondary battery according to any of claims 32 to 34, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

36. A charging equipment for a secondary battery, comprising:

a circuit connecting a secondary battery and a capacitor to a power source in parallel, and

a switching means for making/breaking a closed loop circuit connecting the secondary battery to the capacitor,

wherein, while the closed loop circuit is broken, the power source applies voltage to the capacitor for a determined time so as to store electricity in the capacitor, and then the closed loop circuit is made so as to transmit the electricity stored in the capacitor to the secondary battery, thereby charging the secondary battery.

37. A charging equipment for a secondary battery according to claim 36, further comprising:

a checking power source for which applying the secondary battery with special charging voltage;

a current detection means for detecting electric current flowing to the secondary battery; and

a current judging means for judging whether electric current detected by the current detection means during application of the special charging voltage is larger than preset standard electric current for finishing charging,

wherein, while the closed loop circuit is broken, the checking power source applies the secondary battery with the special charging voltage, and electric current flowing to the secondary battery from the checking power source is detected and compared with the standard electric current for finishing charging, and

wherein, if the detected electric current is larger than the standard electric current for finishing charging, said storage of electricity in the capacitor and transmission of electricity to the secondary battery are repeated;

otherwise, charge of the secondary battery is halted.

38. A charging equipment for a secondary battery according to claim 37, wherein the special charging voltage is equilibrium voltage equaling electromotive force of the secondary battery in a fully charged condition.

39. A charging equipment for a secondary battery according to claim 36, further comprising:

a voltage detection means for detecting open-circuit voltage of the secondary battery; and

a voltage judging means for comparing the open-circuit voltage of the secondary battery detected by the voltage detection means with equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition,

wherein, while the closed loop circuit is broken, the open-circuit voltage is detected and compared with the equilibrium voltage, and

wherein, if the detected open-circuit voltage is larger than the equilibrium voltage, said storage of electricity in the capacitor and transmission of electricity to the secondary battery are repeated;

otherwise, charge of the secondary battery is halted.

40. A charging equipment for a secondary battery according to any of claims 36 to 39, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

41. A charging equipment for a plurality of secondary batteries, comprising:

a charging voltage control means for applying charging voltage to a secondary battery;

a control means for monitoring a charged condition of the secondary battery; and

a battery switching means for switching a secondary battery selected among the plurality of secondary batteries to be charged basing on a signal for finishing charging issued from the control means.

42. A charging equipment for a plurality of secondary batteries according to claim 41, further comprising:

a checking voltage control means for applying equilibrium voltage to a secondary battery while monitoring a charged condition of the secondary battery, the equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition;

a voltage switching means for switching voltage between the charging voltage and the equilibrium voltage, that is, checking voltage; and

a current detection means for detecting electric current flowing through the secondary battery to which the check voltage is applied, wherein the control means monitors a charged condition of the secondary battery basing on the signal from the current detection means.

43. A charging equipment for a plurality of secondary batteries according to claim 41, further comprising:

a voltage switching means for switching on/off application of charging voltage to the secondary battery; and

a voltage detection means for detecting open-circuit voltage of a secondary battery while switching off application of charging voltage,

wherein the control means monitors a charged condition of the secondary battery basing on the signal from the voltage detection means.

44. A charging equipment for a plurality of secondary batteries according to any of claims 41 to 43, wherein the charging voltage is a special charging voltage for supplying the secondary battery with charging electric current of peak or almost peak value, and wherein the special charging voltage is larger than equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition and does not reach a region of voltage causing irreversible chemical reaction in the secondary battery.

45. A charging equipment for a secondary battery according to any of claims 41 to 44, further comprising:

an informational means for giving information of a time required to charge each secondary battery, a charging rate of each secondary battery, a charged condition of each secondary battery whether charge of the secondary battery is finished or not.

46. A charging equipment for a secondary battery according to any of claims 41 to 45, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

47. A charging equipment for a plurality of secondary batteries, comprising:

a battery switching means for switching a secondary battery to be charged from the last charged secondary battery to an uncharged secondary battery,

wherein the secondary batteries are charged one by one.

48. A charging equipment for a plurality of secondary batteries, comprising:

a voltage supply means for applying voltage to a secondary battery,

a group of the plurality of secondary batteries connected to the voltage supply means in series,

wherein the secondary batteries of the group are charged one by one by switching a secondary battery to be charged from the last charged secondary battery to an uncharged secondary battery.

49. A charging equipment for a plurality of secondary batteries according to claim 48, wherein a plurality of the groups are connected to the voltage supply means in parallel, and

wherein all secondary batteries of one group are completely charged, and then each secondary battery of another next group is charged.

50. A charging equipment for a plurality of secondary batteries according to claim 48, wherein the charging equipment can simultaneously charge the plurality of groups of secondary batteries.

51. A charging equipment for a plurality of secondary batteries according to any of claims 48 to 50, wherein the plurality of groups of secondary batteries may be used in either parallel or series.

52. A charging equipment for a plurality of secondary batteries according to any of claims 48 to 51, further comprising:

a short-circuit means for short-circuiting the secondary battery between its terminals after applying special charging voltage for supplying the secondary battery with charging electric current of peak or almost peak value for a predetermined time and before switching applied voltage to equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition, wherein the special charging voltage is larger than the equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the secondary battery.

53. A charging equipment for a plurality of secondary batteries according to any of claims 48 to 51, further comprising:

a cooling means for cooling an exothermic section in the charging equipment.

54. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a voltage detection means for detecting voltage of the secondary battery; and

a judging means for judging whether voltage of the charged secondary battery detected by the voltage detection means is larger than recharging voltage, which is smaller than equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition, or not,

wherein, if the judging means judges that the detected voltage of the charged secondary battery is not larger than the recharging voltage, the secondary battery is recharged by supplying charging voltage from the voltage supply means.

55. A charging equipment for a secondary battery, charging a secondary battery by:

repeating a charging operation cycle including check of a charged condition of a secondary battery and application of special charging voltage to the secondary battery for a predetermined time, wherein a relaxation time is established between the charging operation cycles; and

halting charge of the secondary battery when it is judged at the check that the secondary battery is fully charged.

56. A charging equipment for a plurality of secondary batteries according to claim 55, charging a plurality of secondary batteries by:

performing a charging turn as a series of the charging operation cycles each of which is performed for each uncharged secondary battery, wherein the charging operation cycles are performed one by one for the respective secondary batteries;

repeating the charging turn for charging the plurality of secondary batteries, wherein the relaxation time is established between the final charging operation cycle in one charging turn and the first charging operation cycle in the next charging turn; and

halting charge of each secondary battery when it is judged at the check that the secondary battery is fully charged.

57. A charging equipment for a secondary battery, comprising:

a voltage supply means for applying voltage to the secondary battery;

a charge control device for controlling charge of the secondary battery; and

a cooling means for cooling an exothermic section in the charging equipment.

58. A charging equipment for a secondary battery, comprising:

a seat for setting the secondary battery; and

a take-off means for taking off the secondary battery from the seat by one-touch operation.

59. A charging equipment for a secondary battery according to claim 58, the take-off means comprising:

an operation member to be pushed down by a user;

a boost member for pushing up the secondary battery set on the seat;

a pivot shaft for rotatably supporting the boost member; and

an energization means attached to the shaft, the energization means energizing the boost member opposite to the direction of the boost member being pushed up,

wherein, by operating the operation member, a part of the boost member arises or sinks above and below the seat.

60. A charging equipment for a secondary battery according to claim 58, wherein the seat is recessed at one side in its longitudinal direction so as to serve as the take-off means.

61. A charging method for a secondary battery, comprising the steps of:

(1) previously storing equilibrium voltage and special charging voltage corresponding to the secondary battery to be charged, the equilibrium voltage for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and the special charging voltage for supplying the secondary battery with charging electric current of peak or almost peak value, wherein the special charging voltage is larger than the equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the secondary battery;

(2) applying the special charging voltage to the secondary battery for a determined time;

(3) switching charging voltage applied to the secondary battery from the special charging voltage to the equilibrium voltage;

(4) detecting electric current flowing through the secondary battery while applying the equilibrium voltage to the secondary battery for a short time;

(5) comparing the detected electric current with standard electric current for finishing charging; and

(6) returning to the step (2) and iterating the above steps when the detected electric current is larger than standard electric current;

otherwise halting charge of the secondary battery.

62. A charging method for a secondary battery, comprising:

previously storing n (n is a natural number more than

     1) equilibrium voltages and n special charging voltages for charging n different kinds of secondary batteries, each of the equilibrium voltages for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and each of the special charging voltages for supplying the secondary battery with charging electric current of peak or almost peak value, wherein each of the special charging voltages is larger than the corresponding equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the corresponding secondary battery; and

charging a secondary battery by first to eighth steps,

the first step of initializing a counter variable k (k=1,2, . . . ,n) to 1;

the second step of applying the kth smallest special charging voltage of the n special charging voltages to the secondary battery for a predetermined time;

the third step of jumping to the sixth step if k is equal to n;

the fourth step of detecting voltage applied to the secondary battery while applying the kth smallest special charging voltage to the secondary battery for the predetermined time;

the fifth step of incrementing the rank of k by 1 and returning to the second step if the detected voltage is larger than the kth smallest special charging voltage;

otherwise passing to the sixth step;

the sixth step of switching charging voltage applied to the secondary battery from the kth smallest special charging voltage to the kth smallest equilibrium voltage of the n equilibrium voltages; and

the seventh step of detecting electric current flowing through the secondary battery while applying the kth smallest equilibrium voltage to the secondary battery for a short time; and

the eighth step of returning to the second step and iterating the above steps if the detected electric current is larger than standard electric current for finishing charging;

otherwise, halting charge of the secondary battery.

63. A charging method for a secondary battery, comprising:

previously storing n (n is a natural number more than

     1) equilibrium voltages and n special charging voltages for charging n different kinds of secondary batteries, each of the equilibrium voltages for establishing equilibrium cell potential of the secondary battery in a fully charged condition, and each of the special charging voltages for supplying the secondary battery with charging electric current of peak or almost peak value, wherein each of the special charging voltages is larger than the corresponding equilibrium voltage and does not reach a region of voltage causing irreversible chemical reaction in the corresponding secondary battery; and

charging a secondary battery by first to eighth steps, the first step of initializing a counter variable k (k=1,2, . . . ,n) to 1;

the second step of applying the kth smallest special charging voltage of the n special charging voltages to the secondary battery for a predetermined time;

the third step of jumping to the sixth step if k is equal to n;

the fourth step of detecting voltage applied to the secondary battery while applying the kth smallest special charging voltage to the secondary battery for the predetermined time;

the fifth step of passing to the sixth step if the voltage detection is the first time or a voltage difference between present and past voltages detected during application of the kth smallest special charging voltage is within a preset range;

otherwise, incrementing the rank of k by 1 and returning to the second step;

the sixth step of switching charging voltage applied to the secondary battery from the kth smallest special charging voltage to the kth smallest equilibrium voltage of the n equilibrium voltages; and

the seventh step of detecting electric current flowing through the secondary battery while applying charging voltage of the kth smallest equilibrium voltage to the secondary battery for a short time; and

the eighth step of returning to the second step and iterating the above steps if the detected electric current is larger than standard electric current for finishing charging;

otherwise, halting charge of the secondary battery.

64. A charging method for a secondary battery, comprising:

observing voltage of the secondary battery completed in charging, and

recharging the secondary battery if the observed voltage is not larger than recharging voltage established to be smaller than equilibrium voltage equaling electromotive force of the secondary battery in a fully charged condition.

65. A charging method for a secondary battery, comprising:

repeating a charging operation cycle including check of a charged condition of the secondary battery and application of charging special charging voltage to the secondary battery for a determined time, wherein a relaxation time is established between the charging operation cycles; and

halting charging the secondary battery when it is judged at the check that the secondary battery is fully charged.

66. A charging method for a plurality of secondary batteries according to claim 65, comprising:

performing a charging turn as a series of the charging operation cycles each of which is performed for each uncharged secondary battery, wherein the charging operation cycles are performed one by one for the respective secondary batteries;

repeating the charging turn for charging the plurality of secondary batteries, wherein the relaxation time is established between the final charging operation cycle in one charging turn and the first charging operation cycle in the next charging turn; and

halting charge of each secondary battery when it is judged at the check that the secondary battery is fully charged.