JPH1198712A - Charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bring a battery to nearly fully discharged state in a short time, by increasing the discharge current until its voltage falls below a predetermined value, and by decreasing the discharge current thereafter. SOLUTION: In a charger 2, while when turning on a refresh switch 6 in the state of a power supply cord 3 being connected with a plug socket 8, the charging of a battery 1 is interrupted to discharge the battery 1 by connecting it with loads present in a refreshing means 13, at this time, a current change- over means 18 changes over the discharge circuits of the means 13 so that its discharge current becomes relatively large. Then, after is maintaining this state until the voltage of the battery 1 falls below a predetermined value, its discharge current is changed over by the current changing-over means 18 so as to become small relatively to maintain this state until its voltage reaches a predetermined value. Thereafter, by using a charging means 12, the control mode of a microcomputer 16 charges the battery 1 until it reaches its fully charged state. As a result, a battery can be discharged in a short time until it reaches its nearly fully discharged state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charger for charging a battery causing a so-called memory effect phenomenon, such as a nickel-cadmium battery or a nickel-metal hydride battery.

[0002]

2. Description of the Related Art It is known that a so-called memory effect phenomenon occurs in a nickel-cadmium battery or a nickel-metal hydride battery when the discharge is stopped while a certain amount of capacity is left at the time of discharging in a charge / discharge cycle. When the memory effect phenomenon occurs, the battery voltage at the time of discharge drops faster than usual, so that the usable time of an electronic device that stops when the battery voltage drops below the drive lower limit voltage becomes shorter.

[0003] As a battery charger for charging this kind of battery, there is a battery charger provided with refresh means for returning a battery having a memory effect phenomenon to a normal state. The refresh means has a configuration in which a constant current flows from a battery to a load, and the battery is discharged until the battery is almost completely discharged. In the conventional charger, a refresh operation by the refresh means (elimination of a memory effect phenomenon) is performed when a user operates a switch.
Is to be implemented.

[0004]

However, in the conventional charger with the refresh function configured as described above, the time required for the refresh to be completed, that is, the time required for the battery to be in a substantially discharge completed state, is reduced. That was the problem. In order to reduce the refresh time, a large current may flow from the battery to the load during the refresh. However, under these discharge conditions, the battery cannot always be completely discharged, and the battery capacity may slightly remain after the refresh is completed.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a charger capable of discharging a battery in a short time until the battery is almost completely discharged.

[0006]

In order to achieve this object, a battery charger according to the present invention is provided with a refresh means for discharging a battery to a substantially completely discharged state, wherein a battery voltage is reduced to a predetermined voltage. And a current switching means for relatively reducing the discharge current after the battery voltage falls below the set voltage.

According to the present invention, the refresh time can be reduced until the battery voltage drops to a predetermined voltage. By making the discharge current relatively small, the battery is discharged until it is almost completely discharged. I do.

According to another aspect of the present invention, there is provided a charger according to the above-described invention, wherein the power supply circuit of the refreshing means and the current switching means and the power supply circuit of the electric device in the charger housing are connected to the battery at the time of refreshing. Means.

According to the present invention, the refreshing means, the current switching means, and the electric equipment in the charger housing also become loads at the time of refreshing.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment Hereinafter, an embodiment of a charger according to the present invention will be described in detail with reference to FIGS. FIG. 1 is a perspective view showing a state where a battery is being charged by the charger according to the present invention, and FIG.
FIG. 3 is a block diagram showing a configuration of the charger, FIG. 3 is a graph showing a change in battery voltage at the time of refreshing, and FIG. 4 is a flowchart for explaining an operation of the charger according to the present invention at the time of refreshing.

In these figures, reference numeral 1 denotes a battery for an electric bicycle, and reference numeral 2 denotes a charger according to this embodiment. The battery 1 includes a battery case 1a and battery cells (not shown) housed in the battery case 1a. The battery cell is a conventionally known nickel-cadmium battery.

The charger 2 derives a power cord 3 from one end of the housing 2a and a battery cord 4 from the other end, and turns on a charging lamp 5 which is turned on when charging and a refresh which is turned on when starting refresh. Switch 6 and refresh lamp 7 that lights up when refreshing
Are provided in the upper part of the housing. The power cord 3 has a plug 3a connected to an outlet 8 of a commercial power supply, and the battery cord 4 has a connector 1b for charging and discharging the battery 1.
(See FIG. 2).

As shown in FIG. 2, an AC power supply for converting a 100 V AC power supply into a DC power is provided in a housing 2 a of the charger 2.
Power supply means 11 comprising a DC / DC converter or a transformer
A charging unit 12 for charging the battery 1, a refreshing unit 13 for performing a refresh,
A display unit 14 having the charging lamp 5 and the refresh lamp 7; a voltage detecting unit 15 for detecting a battery voltage; and a microcomputer 16 for controlling the charging unit 12 and the refreshing unit 13
And a fan 17 for ventilating the inside of the housing 2a. The refresh switch 6 is connected to the microcomputer 16.

The charging means 12 supplies a charging current to the battery 1 by connecting the power cord 3 to the outlet 8 and connecting the battery cord 4 to the battery 1. The charging means 12 does not charge when a refresh signal is input from a microcomputer 16 described later.

The refresh means 13 has a load such as a resistor (not shown), and when a refresh signal is input from the microcomputer 16, the battery 1
Is connected to the load and the battery 1 is refreshed. The refresh means 13 switches the discharge current during the refresh between the first half and the second half of the discharge. Current switching means 18
As shown in FIG. 3, the discharge current is relatively increased until the battery voltage at the time of refresh falls to a predetermined voltage A (V), and the discharge current is increased after the battery voltage falls below A (V). Is relatively small. In FIG. 3, a solid line indicates a change in battery voltage when refreshing is performed by the charger 2 according to this embodiment, and a two-dot chain line indicates a change in battery voltage when refreshing is performed by a conventional charger. Note that the battery voltage is detected by the voltage detecting means 15.

The microcomputer 16 sends a charge lamp lighting signal to the display means 14 to light the charge lamp 5 while the charging by the charging means 12 is being performed. When the refresh switch 6 is turned on, the microcomputer 16 shifts from the charging mode to the refresh mode, sends a refresh signal to the charging means 12 and the refreshing means 13, and sends a refresh lamp lighting signal to the display means 14. Then, the refresh lamp 7 is turned on.

The refresh mode ends when the battery voltage reaches the refresh end voltage B (V). After the refresh is completed, the mode shifts to the charging mode.
The microcomputer 16 is configured to cut off the power supply by the power supply unit 11 after the charging is completed. The microcomputer 16 drives the fan 17 during charging and refreshing to ventilate the inside of the charger housing 2a.

The battery charger 2 configured as described above charges the battery 1 by connecting the power cord 3 to the outlet 8 and connecting the battery cord 4 to the battery 1. Further, when the refresh switch 6 is turned on in the above-described state, the charger 2 is turned on.
Stops charging and executes refresh for the battery 1. That is, the battery 1 is connected to the load in the refreshing means 13 and discharged. At this time, the refresh lamp 7 is turned on. During charging and refreshing, the fan 17 ventilates the inside of the charger housing 2a.

At the time of refreshing, first, as shown in step S1 of the flowchart shown in FIG. 4, the current switching means 18 switches the discharging circuit so that the discharging current becomes relatively large. The state in which this large current flows is determined in step S2.
The battery voltage Vb is a predetermined A (V) as shown by
Maintain until: After the battery voltage Vb satisfies the above condition, as shown in step S3, the current switching means 18 switches the discharge circuit so that the discharge current becomes relatively small.

The state where the discharge current is relatively small is maintained until the battery voltage Vb reaches a predetermined voltage B (V), as shown in step S4. After the battery voltage Vb reaches the voltage B (V), the control mode of the microcomputer 16 shifts from the refresh mode to the charging mode in step S5, and the charging unit 12 charges the battery 1 until the battery 1 is fully charged. After the charging is completed, the microcomputer 16 cuts off the power supply by the power supply means 11, and the charger 2 is turned off.

According to the charger 2 shown in this embodiment, a large current flows until the battery voltage Vb drops to a predetermined voltage B (V) at the time of refresh, and the battery 2 is discharged to shorten the refresh time. Can be. For this reason,
The time required for completing the refresh can be reduced from the conventional time T to the time T1. In addition, at the end of the refresh, the battery is discharged by supplying a small current, so that when the refresh is completed, the battery can be brought into a substantially completely discharged state as in the related art.

Second Embodiment A charger according to another invention will be described in detail with reference to FIG.
FIG. 5 is a block diagram showing a configuration of a charger according to another invention. In FIG. 5, the same or equivalent members as those described in FIG. 1 and FIG. .

The charger 2 shown in FIG. 5 has a power supply switching means 21 for changing the power supply to the battery 1 at the time of refreshing. When the control mode of the microcomputer 16 is the refresh mode, the power supply switching means 21 connects the power supply circuit of each electronic component of the charger 2 to the power supply means 1.
1 is connected to the battery 1 instead.
That is, at the time of refreshing, the refresh lamp 7, the refreshing means 13, the voltage detecting means 15, the microcomputer 16 and the fan 17 become loads on the battery 1.

For this reason, the power consumption of the battery 1 at the time of refreshing is increased as compared with the case of employing the first embodiment, so that the refresh time can be further reduced. Moreover, the refresh can be performed without using a commercial power supply.

In the first and second embodiments, an example in which the battery 1 having a nickel-cadmium battery is used has been described. However, the battery 1 has a memory effect such as a nickel-hydrogen battery. Other batteries that cause the phenomenon may be used.

[0026]

As described above, according to the present invention, the refresh time can be reduced until the battery voltage drops to a predetermined voltage, and the battery can be substantially reduced by making the discharge current relatively small. Discharge until completely discharged.

Therefore, it is possible to provide a charger which can discharge the battery in a short time until the battery is almost completely discharged.

According to another invention in which the power supply circuit such as the refresh means and the current switching means is connected to the battery at the time of refreshing, the refresh means, the current switching means and the electric equipment in the charger housing also become loads at the time of refreshing. And the refresh time can be reduced. Also, there is an effect that the refresh can be performed without using a commercial power supply.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a battery is being charged by a charger according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a charger.

FIG. 3 is a graph showing a change in battery voltage during refresh.

FIG. 4 is a flowchart for explaining an operation at the time of refresh of the charger according to the present invention.

FIG. 5 is a block diagram showing a configuration of a charger according to another invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Battery, 2 ... Charger, 12 ... Charging means, 13 ...
Refresh means, 16 microcomputer, 17
... Fan, 18 ... Current switching means, 21 ... Power supply switching means.

Claims (2)

[Claims] 1. A charger provided with refreshing means for discharging a battery to a substantially completely discharged state,
The refresh means includes a current switching means for relatively increasing the discharge current until the battery voltage drops to a predetermined voltage, and for relatively reducing the discharge current after the battery voltage falls below the set voltage. A charger characterized in that: 2. The battery charger according to claim 1, further comprising a power supply circuit for refreshing means and a current switching means, and a power supply switching means for connecting a power supply circuit of an electric device in a charger housing accommodating them to a battery at the time of refreshing. A charger comprising: