JP2007195367A - Charging system and charging program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging system capable of securing stable charge capacity of a secondary battery at finish of charging, and capable of avoiding a difference in the charge capacity at finish of charging, according to a deterioration state of the battery. <P>SOLUTION: When a charging current I from a charging circuit 1 becomes a predetermined value (for example, 200 mA) or less, a charge control unit 3 sets at a value at a remaining timer 4 of which value is obtained by adding a corrected value to a default value, wherein the corrected value is that corresponding to a degree of deterioration of the secondary battery 2, namely corresponding to the number of charging times. When clocking by the remaining timer 4 is started, and the clocking by the remaining timer 4 passes a deadline, it is judged that the battery is fully charged and a switch control signal S is supplied to a charging circuit 3 to finish charging. With such constitution, charging time is extended by extending a clocking period by the remaining timer 4 only by the short charging time according to the degree of deterioration of the secondary battery 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a charging device and a charging program.

  Mobile devices such as mobile phones, digital cameras, and PDAs often use secondary batteries (such as lithium ion batteries) that can be charged to a power source. In such a portable device, when charging the secondary battery, with a certain margin for battery protection, when the charging current falls below a predetermined value, it is determined that the battery is fully charged, and then a timer is started for a predetermined time. A technique has been proposed in which additional charging is performed for an insufficient charging capacity and charging is terminated when the timer expires (see, for example, Patent Document 1).

JP 10-312011 A

  However, in the above prior art, since the timer value is fixed to a value assumed when the secondary battery satisfies a predetermined reference value, that is, when the battery is not deteriorated, the secondary battery seems to be deteriorated. In such a case, there is a problem that the charging capacity is insufficient in the additional charging with the timer value.

  Therefore, according to the present invention, in the charging system that performs additional charging after full charging, the additional charging time is controlled in accordance with the battery deterioration status, so that the charging capacity at the end of charging differs depending on the battery deterioration status. It is an object of the present invention to provide a charging device, a charging method, and a charging program capable of avoiding the occurrence of a problem and ensuring a stable charging capacity for a secondary battery at the end of charging.

  In order to achieve the above object, the inventions of claims 1 and 7 detect a charging current for the secondary battery, determine whether or not the secondary battery is fully charged based on a change in the charging current, and If it is charging, the deterioration state of the secondary battery is detected, an additional charging time is set according to the deterioration state of the secondary battery, and the charging of the secondary battery is terminated after the additional charging time has elapsed. Let

  Further, as a preferred aspect, for example, as in claim 2, in the charging device according to claim 1, the full charge determination means determines whether the secondary battery has a predetermined current value or not. It may be determined whether or not the battery is fully charged.

  As a preferred mode, for example, as in claim 3, in the charging device according to claim 1, the deterioration state detecting means may detect the deterioration state based on the number of times of charging the secondary battery.

  Further, as a preferred aspect, for example, as in claim 4, the charging device according to claim 3, further comprising an additional charging time table for storing an additional charging time according to the number of times of charging the secondary battery, The charging time setting means may set an additional charging time according to the number of times of charging the secondary battery stored in the additional charging time table.

  Further, as a preferred aspect, for example, as in claim 5, in the charging device according to claim 1, the additional charging time setting means does not depend on presence or absence of battery deterioration when the secondary battery is in a deteriorated state. A value obtained by adding a correction time corresponding to the deterioration state of the secondary battery to the default time may be set as the additional charging time.

  Further, as a preferred aspect, for example, as in claim 6, in the charging device according to claim 5, the additional charging time setting means corrects the default time longer as the deterioration of the secondary battery progresses. Time may be added and set as the additional charging time.

  According to the first and seventh aspects of the present invention, when the charging current for the secondary battery is detected, it is determined whether the secondary battery is fully charged based on the change in the charging current, and the battery is fully charged. , Detecting a deterioration state of the secondary battery, setting an additional charging time according to the deterioration state of the secondary battery, and terminating the charging of the secondary battery after the elapsed time of the additional charging time. Therefore, it is possible to control the additional charging time according to the battery deterioration status, and to avoid a difference in charge capacity at the end of charging according to the battery deterioration status. In contrast, an advantage that a stable charge capacity can be secured is obtained.

  Further, according to the invention of claim 2, since the full charge determining means determines whether or not the secondary battery is fully charged depending on whether or not the charging current has reached a predetermined current value. It is possible to avoid a difference in charging capacity at the end of charging according to the deterioration state of the battery, and to obtain an advantage that a stable charging capacity can be secured for the secondary battery at the end of charging. .

  According to the invention described in claim 3, since the deterioration state is detected based on the number of times the secondary battery is charged by the deterioration state detecting means, the charge capacity at the end of charging is determined according to the deterioration state of the battery. A difference can be avoided, and an advantage that a stable charging capacity can be secured for the secondary battery at the end of charging can be obtained.

  According to the invention of claim 4, the additional charging time setting means sets the additional charging time according to the number of times of charging the secondary battery stored in the additional charging time table. It is possible to avoid a difference in charge capacity at the end of charging depending on the deterioration state, and to obtain an advantage that a stable charge capacity can be secured for the secondary battery at the end of charging.

  According to the fifth aspect of the present invention, when the secondary battery is in a deteriorated state, the additional charge time setting means adds a correction time corresponding to the deteriorated state of the secondary battery to a default time that does not depend on the presence or absence of the battery deterioration. As the additional charging time is set as the additional charging time, the additional charging time can be controlled according to the battery deterioration status, and the charge capacity at the end of charging varies depending on the battery deterioration status. Thus, there is an advantage that a stable charging capacity can be secured for the secondary battery at the end of charging.

  According to the sixth aspect of the invention, the additional charging time setting means adds the longer correction time to the default time and sets the additional charging time as the secondary battery deteriorates. The additional charging time can be controlled according to the battery deterioration status, and it is possible to avoid a difference in the charging capacity at the end of charging according to the battery deterioration status. On the other hand, there is an advantage that a stable charging capacity can be secured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A. Configuration of Embodiment FIG. 1 is a block diagram showing a configuration of a charging device according to an embodiment of the present invention. In the figure, a charging circuit unit 1 rectifies and smoothes an AC power source such as a commercial power source, supplies a constant voltage and a constant current to a secondary battery 2, and charges the secondary battery 2. In addition, the charging circuit unit 1 supplies the charging current I to the charging control unit 3 and ends the charging of the secondary battery 2 when the switch control signal S is supplied from the charging control unit 3. The secondary battery 2 is a rechargeable battery such as a lithium ion battery.

  When the charging current I from the charging circuit unit 1 becomes a predetermined value (for example, 200 mA) or less, the charging control unit 3 acquires the charging number of the secondary battery 2 from the charging number counter 5, and according to the acquired charging number, The additional charging time of the remaining timer 4 is acquired from the additional charging time table 6. The additional charging time is a default value when the secondary battery 2 is not deteriorated, and when the secondary battery 2 is deteriorated, the default value is corrected according to the degree of deterioration (number of times of charging). The value is the sum of the values. Therefore, the charging control unit 3 sets a default value (for example, 20 minutes) in the remaining timer 4 when the number of times of charging the secondary battery 2 is equal to or less than a predetermined value (for example, 100 times), that is, has not deteriorated. When the secondary battery 2 is deteriorated, a value obtained by adding a correction value corresponding to the number of times of charging to the default value is set in the remaining timer 4.

  In addition, after setting the additional charging time to the remaining timer 4, the charging control unit 3 starts counting by the remaining timer 4, and when the time measured by the remaining timer 4 is up, the charging control unit 3 determines that the charging is full and the charging circuit The switch control signal S is supplied to the unit 3 to terminate the charging. Therefore, when the secondary battery 2 is deteriorated, it is charged for a longer time by a correction value corresponding to the number of times of charging. The remaining timer 4 measures the additional charging time set by the charging control unit 3.

  The charge number counter 5 increments the charge number of the secondary battery 2 every time it is charged, holds the latest charge number, and supplies the charge number to the charge control unit 3 as required. As shown in FIG. 2, the additional charging time table 6 holds a correction value for each number of times of charging and an additional charging time for the number of times of charging. In the illustrated example, the correction value is “0 (minutes)” when the number of times of charging is 0 to 100, and the correction value is “10 (minutes)” when the number of times of charging is 100 to 200. The correction value is “10 (minutes)” between 200 and 300, and the correction value is “35 (minutes)” when the number of times of charging is 300 or more. In this case, the default value is 20 minutes.

  Here, determination of full charge between a new secondary battery and a deteriorated secondary battery will be described. FIG. 3 is a conceptual diagram for explaining determination of full charge between a new secondary battery and a deteriorated secondary battery. When the secondary battery is new (not deteriorated), the time T1 is from when the charging current reaches a predetermined value (200 mA in the illustrated example) until it can be determined to be fully charged (about 80 to 90 mA). In contrast, in the case of a deteriorated secondary battery, only the time T2 (T2> T1) is required. That is, it takes time until the deteriorated secondary battery is fully charged. In the present embodiment, the charging time is extended by extending the time measured by the remaining timer 4 by the insufficient charging time (T2-T1) according to the degree of deterioration of the secondary battery 2, that is, the number of times of charging. ing.

B. Operation of Embodiment Next, the operation of the above-described embodiment will be described. Here, FIG. 4 is a flowchart for explaining the operation of the charging apparatus according to the present embodiment. First, when the secondary battery 2 is connected, the charging circuit unit 1 rectifies and smoothes an AC power source such as a commercial power source to supply a constant voltage and a constant current to the secondary battery 2 to start charging (step) S10). Next, the charging control unit 3 determines whether or not the charging current I from the charging circuit unit 1 has fallen below a predetermined value (200 mA) (step S12).

  When the charging current I is not less than the predetermined value (200 mA), the charging of the secondary battery 2 is continued. On the other hand, when the charging current I falls below a predetermined value (200 mA), the charging number of the secondary battery 2 is acquired from the charging number counter 5 (step S14), and the additional charging time table 6 is obtained according to the acquired charging number. The additional charging time (or correction value) of the remaining timer 4 is acquired from the above, and the additional charging time (or default value + correction value) is set in the remaining timer 4 (step S16). That is, when the number of times of charging is 0 to 100 and the secondary battery 2 is not deteriorated, a default value (20 minutes) is set, and when the number of times of charging is 100 times or more and the secondary battery 2 is deteriorated. Sets the remaining timer 4 by adding a value corresponding to the degree of deterioration (number of times of charging) to the default value.

  Next, the charging control unit 3 starts counting the additional charging time by the remaining timer 4 (step S18), and determines whether or not the timing by the remaining timer 4 has expired (step S20). If the remaining timer 4 has not expired, the secondary battery 2 continues to be charged. On the other hand, when the time measured by the remaining timer 4 is up, it is determined that the battery is fully charged (step S22), and the switch control signal S is supplied to the charging circuit unit 3 to terminate the charging (step S24). Next, the number of times of charging the secondary battery 2 is incremented and the process is terminated (step S26).

  Therefore, when the secondary battery 2 is deteriorated, it is charged for a longer time by the correction value corresponding to the number of times of charging, and the additional charging time can be controlled according to the battery deterioration state. In addition, it is possible to avoid a difference in charge capacity at the end of charging according to the battery deterioration state, and it is possible to ensure a stable charge capacity for the secondary battery at the end of charging.

It is a block diagram which shows the structure of the charging device by embodiment of this invention. It is a conceptual diagram which shows the data structure of an additional charge time table. It is a conceptual diagram explaining determination of a full charge with a new secondary battery and a deteriorated secondary battery. It is a flowchart for demonstrating operation | movement of the charging device by this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charging circuit part 2 Secondary battery 3 Charge control part (Charging current detection means, full charge judgment means, deterioration state detection means, additional charge time setting means, charge control means)
4 Remaining timer (time measuring means)
5 Charge counter (degradation state detection means)
6 Additional charging time table (Additional charging time table)

Claims (7)

A charging device for charging a secondary battery,
Charging current detecting means for detecting a charging current for the secondary battery;
Full charge determination means for determining whether or not the secondary battery is fully charged based on a change in charge current detected by the charge current detection means;
A deterioration state detecting means for detecting a deterioration state of the secondary battery;
An additional charge time setting means for setting an additional charge time according to the deterioration state of the secondary battery detected by the deterioration state detection means;
After the full charge is detected by the full charge determination means, the time measuring means for counting only the additional charge time set by the additional charge time setting means,
A charging device comprising: charging control means for terminating charging of the secondary battery after elapse of an additional charging time by the time measuring means.   The charging device according to claim 1, wherein the full charge determination unit determines whether or not the secondary battery is fully charged depending on whether or not the charging current has reached a predetermined current value.   The charging device according to claim 1, wherein the deterioration state detecting unit detects a deterioration state based on the number of times of charging the secondary battery. An additional charging time table storing additional charging time according to the number of times of charging the secondary battery;
The charging device according to claim 3, wherein the additional charging time setting means sets an additional charging time corresponding to the number of times of charging the secondary battery stored in the additional charging time table.   When the secondary battery is in a deteriorated state, the additional charge time setting means sets a value obtained by adding a correction time corresponding to the deterioration state of the secondary battery to a default time that does not depend on the presence or absence of the battery deterioration. The charging device according to claim 1, wherein the charging device is set as time.   6. The charging device according to claim 5, wherein the additional charging time setting means adds a longer correction time to the default time as the deterioration of the secondary battery progresses, and sets the additional charging time as the additional charging time. . A charging program for charging a secondary battery,
On the computer,
Charging current detection function that detects the charging current for the secondary battery,
A full charge determination function for determining whether or not the secondary battery is fully charged based on a change in the charge current;
A deterioration state detection function for detecting a deterioration state of the secondary battery;
An additional charge time setting function for setting an additional charge time according to the deterioration state of the secondary battery when full charge is detected after the start of charging the secondary battery;
A time keeping function for keeping time for the additional charging time after the full charge is detected;
A charging program that realizes a charge control function for terminating charging of the secondary battery after the additional charging time has elapsed.

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