JPH05344659A - Secondary battery charger with discharge function - Google Patents

Abstract

PURPOSE:To shorten an apparent charging time of a secondary battery and to eliminate user's consideration of a discharging period of the battery by discharging it at a certain special number of times without discharging the battery at every time. CONSTITUTION:The secondary battery charger with a discharge function comprises a secondary battery 1 to be charged and discharged, a charge/ discharge changeover switch 2, a discharging circuit 3, a charging circuit 4, and a charge/discharge switching controller 6. Particularly when the battery 1 is mounted in the charger, the number of times of this case is detected, and a discharging function is operated at a special number of times. In order to conduct this operation, a charging number detector 5 and a holding circuit 7 are newly provided in the charger. Thus, simple circuits 5, 7 are added to reduce a memory effect of the battery 1 without user's labor, and an available time of the battery 1 can be prolonged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to discharge function control in a secondary battery charging device.

[0002]

2. Description of the Related Art In the case of charging a secondary battery (storage battery) such as a nickel-cadmium battery, when the secondary battery which is supposed to be sufficiently charged is actually used, the usage time becomes short. In order to reduce the existing memory effect, it is necessary to discharge.

Conventionally, when discharging a secondary battery,
As a method, a method of discharging before charging each time, and a method of discharging when the user remembers how many times the secondary battery has been charged and the number of times increases to some extent,
There is a method in which the user performs a discharge and then discharges after the memory effect occurs.

The method of discharging each time is disadvantageous in that it takes a long time before the secondary battery can be used because both discharging and charging are performed every time.

The method in which the user remembers the number of times of charging has a disadvantage that it becomes difficult to remember the number of times of charging when the user has a plurality of secondary batteries.

The method of not discharging until the memory effect occurs has the drawback that the user must confirm the memory effect of the secondary battery by himself.

As described above, there is a problem in any of the above methods, and the usability is not very good for the user.

[0008]

SUMMARY OF THE INVENTION In the above-mentioned prior art, in the case of charging a secondary battery which needs to be discharged in order to reduce the memory effect in which the secondary battery cannot exhibit 100% capacity, The problem that apparently it takes time to charge because it discharges and charges in one charge like
There was a problem that the user had to decide the discharge time of the secondary battery by himself as in the case of.

An object of the present invention is to provide a method capable of shortening the apparent charging time of the secondary battery and automatically operating the discharging function so that the user does not have to consider the discharging time of the secondary battery. is there.

[0010]

In order to achieve the above object, the present invention first detects how many times the secondary battery is charged when the secondary battery is attached to the charging device, and then, at every specific number of times. In order to perform this operation, a charging frequency detection circuit and a holding circuit are newly provided in the charging device.

[0011]

[Function] When the secondary battery is mounted on the charging device, the charge number detection circuit in the charger detects whether the charge is the number of times after the last discharge, and the discharge function is activated at a certain number of times. It works and discharges the secondary battery.

In addition, when several types of secondary batteries can be charged, a holding circuit is provided for each type of the secondary battery, and the discharging function is activated for each type to discharge the secondary battery.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram showing this embodiment. 1 is a secondary battery to be charged / discharged, 2 is a charge / discharge switch,
3 is a discharging circuit, 4 is a charging circuit, 5 is a charging frequency detecting circuit,
6 is a charge / discharge switching control circuit, and 7 is a holding circuit.

In this block diagram, when the rechargeable battery No. 1 is attached to this charging device, the charge / discharge changeover switch No. 2 is usually on the charging circuit side No. 4 so that the rechargeable battery No. 1 is charged. ing. At this time, a signal is sent to the charge number detection circuit of 5. The number of times of charging is held in the holding circuit of 7. When the charging of the secondary battery reaches a certain number of times, the charge number detection circuit 5 sends a signal to the charge / discharge switching control circuit 6, and the charge / discharge switching control circuit 6 controls the charge / discharge switching switch 2 Are switched from the charging circuit side of 4 to the discharging circuit side of 3. By doing so, the secondary battery of No. 1 is discharged. When the discharging is completed, the charging / discharging switching control circuit 6 automatically switches the charging / discharging switching switch 2 to the charging circuit 4 side to start charging. At the same time, the charging number detection circuit 5 and the holding circuit 7 are operated to be initialized, and this is repeated thereafter.

Next, a specific number N of times of starting the discharge will be described with reference to FIG. Figure 2 shows the discharge start count N when the user has a few rechargeable batteries of the same type.
2 and 3 respectively. When the number of secondary batteries used by the user is one, since only one secondary battery is discharged, the discharge start count N can be set to some extent freely. However, when the number of secondary batteries is plural, it cannot be set so freely. For example, when the user uses two secondary batteries of the same type and alternately charges the secondary batteries as shown in FIG.
When is a multiple of 2, only one side of the two secondary batteries is discharged, and the other secondary battery is not discharged. Similarly, in the case of using three secondary batteries as shown in FIG. 2B, if N is a multiple of 3, two out of three will not be discharged. If the number of secondary batteries is 4, a multiple of 4 is used, and if the number of secondary batteries is 5, a multiple of 5 is used. In the same manner, only one battery is discharged and the others are not discharged. In general, it is quite rare for ordinary users to use dozens of secondary batteries of the same type, so there is a possibility that only specific secondary batteries can be discharged by selecting a value of N that is a relatively large prime number. Can be lowered.

Next, a case where there are several types of secondary batteries will be described with reference to FIG. FIG. 3 shows the case where there are two types of secondary batteries. 1, 2, 3, 4, 5, 6 are the same as in FIG.
Further, 8 secondary battery type detection circuits are added.
Further, 7-1 and 7-2 are holding circuits. As many holding circuits as the number of types of secondary batteries that can be charged by the charging device are prepared. In the operation, when the secondary battery 1 is attached to the charging device, the type of the secondary battery is first detected by the secondary battery type detection circuit 8 and the corresponding holding circuit 7 is selected. That is, either 7-1 or 7-2 is selected. After that, the operation is similar to that of FIG. By doing so, even if there are many types of secondary batteries, it operates so as to determine whether or not to discharge based on the value for each type. By doing so, it becomes possible to discharge each type of secondary battery.

[0017]

As described above, by adding the simple circuit as described above, the memory effect of the secondary battery can be reduced and the period of use of the secondary battery can be extended without bothering the user. You can Also, the apparent charging time is almost unchanged.

[Brief description of drawings]

FIG. 1 is a block diagram of a secondary battery charging device with a discharging function according to an embodiment of the present invention.

FIG. 2 is a charge-discharge state transition diagram of a secondary battery charging device with a discharging function according to an exemplary embodiment of the present invention.

FIG. 3 is a block diagram of a secondary battery charging device with a discharging function when two types of secondary batteries according to an embodiment of the present invention can be charged.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Secondary battery to be charged, 2 ... Charging / discharging changeover switch, 3 ... Discharge circuit, 4 ... Charging circuit, 5 ... Charging frequency detection circuit, 6 ... Charge / discharge switching control circuit, 7 ... Holding circuit (7-
1 ... Holding circuit 1, 7-2 ... Holding circuit 2), 8 ... Secondary battery type detection circuit.

Claims (3)

[Claims] 1. A secondary battery charging device having a discharge function built-in, wherein a user mounts the secondary battery on the charging device to automatically discharge the secondary battery, and the secondary battery is discharged every time. A secondary battery charging device with a discharging function, characterized in that the battery is discharged at a specific number of times. 2. The secondary battery charging device with a discharging function according to claim 1, wherein a certain number of times when the secondary battery is discharged is set to be a prime number. 3. The secondary battery charging device with a discharging function according to claim 1, wherein the secondary battery charging device has a certain number of times for each type of secondary battery used.