JP2004260983A - Method for discharging secondary cell and capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently discharge residual power of a secondary cell and a capacitor in a short period of time, while preventing the occurrence of a polarity inversion phenomenon of the secondary cell. <P>SOLUTION: In a method for discharging inside power of the secondary cell and the capacitor in a short period of time, a discharging current is increased until a voltage of the cell becomes equal to a reference voltage. When the cell voltage becomes equal to the reference voltage, the discharge is suspended for a certain period of time. Such operations are repeated that the discharging current is increased until the cell voltage becomes equal to the reference voltage again. A means is used that the discharging is stopped at the time when the discharging current does not increase up to the reference current. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
The present invention relates to a secondary battery and a method for discharging a capacitor.
[0002]
2. Description of the Related Art Among secondary batteries, a nickel cadmium battery and a nickel hydride battery, in particular, cause a phenomenon called a memory effect depending on use conditions, and this may cause the performance of the battery to deteriorate before the original life of the battery. Has become. In recent years, the use environment of the battery requires a reduction in the charging time, and accordingly, a reduction in the discharging time is also required. The memory effect is a phenomenon in which the nominal power capacity of the battery cannot be sufficiently obtained when the battery is used while performing additional supplementary charging without discharging the entire power capacity of the battery. In order to prevent this phenomenon, it is necessary to sufficiently discharge the remaining power of the battery before charging the battery. Therefore, the discharge end voltage of the battery needs to be set low.
[0003] However, when the batteries are used as a series assembled battery using a plurality of batteries, the individual batteries have different capacities and the end timing of discharge of each battery is different. As a result, when the discharge end voltage of the battery is set to a low voltage, the battery having no remaining power in the assembled battery, that is, the battery having the voltage of 0 V first, is supplied with the power from the battery having the remaining power. The battery will be flooded, causing catastrophic damage to the battery. This is called a battery reversal phenomenon.
In the conventional method in which the discharge is performed up to the discharge end voltage by the constant current discharge, the discharge end voltage cannot be set low because of the possibility of the reversal phenomenon, and the remaining power of the battery is sufficiently discharged. It is difficult. Also, if the constant current discharge value is increased to shorten the discharge time, it is difficult to sufficiently discharge the remaining power of the battery, and if the constant current discharge value is reduced, it is possible to approximately discharge the remaining battery power. There is a problem that the discharge time becomes longer.
As described above, when the constant current discharge value is reduced to perform the discharge, the remaining power of the battery is roughly discharged. However, the remaining power actually exists in the battery. However, when the discharge is stopped, the battery voltage rises above the discharge end voltage, and it cannot be said that the battery is sufficiently discharged. This is particularly conspicuous in small-sized and high-capacity batteries, and is called a dielectric absorption phenomenon.
Further, the above-mentioned dielectric absorption phenomenon also occurs in a capacitor, and there is a problem that a capacitor that has not been sufficiently discharged destroys other mounted components when mounting a substrate during product production.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to sufficiently discharge the remaining power of a secondary battery and a capacitor in a short time while preventing the occurrence of the turning phenomenon.
[0008]
In order to achieve the above object, in a method for discharging the internal power of a secondary battery and a capacitor in a short time, a discharge current is increased until the battery voltage becomes equal to a reference voltage. When the battery voltage becomes equal to the reference voltage, the discharge is stopped for a certain period of time, and the operation of increasing the discharge current again until the battery voltage becomes equal to the reference voltage is repeatedly performed. A means is used in which the discharge is terminated when the voltage no longer rises.
[0009]
Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram in which the discharging method of the present invention is implemented. As shown in FIG. 1, an analog-to-digital converter 2 connected to the battery 1 and measuring the voltage of the battery 1, an electronic load 3 for discharging the battery 1, and an output from the analog-to-digital converter 2 The control unit 4 includes a control unit 4 that controls the load 3, and a current measurement unit 5 that measures a current between the battery 1 and the electronic load 3 and outputs current information to the control unit 4.
The operation when the battery 1 is discharged according to the present invention with this configuration will be described. When the battery 1 is connected, the voltage information of the battery 1 output from the analog-to-digital converter 2 is compared with the reference voltage by the controller 4, and if the voltage of the battery 1 is higher than the reference voltage, the control is performed. Under the control of the unit 4, the electronic load 3 increases the discharge current until the voltage of the battery 1 becomes equal to the reference voltage. When the voltage of the battery 1 becomes equal to the reference voltage, the electronic load 3 stops discharging for a certain period of time under the control of the control unit 4, and the electronic load 3 again controls the battery 1 under the control of the control unit 4. The operation of increasing the discharge current until the voltage of the reference voltage becomes equal to the reference voltage is repeatedly executed. Upon receiving the current information from the current measuring unit 5 and when the discharge current measured by the control unit 4 does not increase to the reference current, the control by the control unit 4 causes the electronic load 3 to terminate the discharge.
[0011]
According to the present invention, since the discharge current of the battery 1 temporarily rises to the upper limit of the internal resistance of the battery 1, it is possible to reduce the battery internal power discharge time. Further, the discharge is stopped for a certain period of time, which is performed to reduce the dielectric absorption phenomenon, without setting the reference voltage, which is the discharge end voltage of the battery 1, to a voltage that is low enough to cause a risk of battery reversal. The internal power of the battery 1 is sufficiently discharged by the repetitive operation of increasing the discharge current again until the battery voltage becomes equal to the reference voltage. Further, even when the battery 1 is replaced with a capacitor, the internal power is sufficiently discharged as described above.
[0012]
[Brief description of the drawings]
FIG. 1 is a block diagram in which a discharge method according to the present invention is implemented.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Battery 2 ... Analog-digital conversion part 3 ... Electronic load 4 ... Control part 5 ... Current measurement part

Claims (1)

In the method of discharging the internal power of the secondary battery and the capacitor in a short time, the discharge current is increased until the battery voltage becomes equal to the reference voltage, and when the battery voltage becomes equal to the reference voltage, the discharge is constant. The discharge is stopped for a time, and the operation of increasing the discharge current again until the battery voltage becomes equal to the reference voltage is repeatedly performed, and the discharge is terminated when the discharge current stops increasing to the reference current. Method.

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