JPH05191931A - Discharge device for cell - Google Patents

Abstract

PURPOSE:To prevent the memory effect from occurring and maintain the capacitance of the cell itself by detecting the disconnected state by use of an ammeter connected between a secondary cell and a load and by operating a discharge switch to make a complete discharge. CONSTITUTION:A secondary cell group 2 is connected to a load 9 through an ammeter 5. By the ammeter 5, it is confirmed that the cell group 2 are not turned on. A discharge switch 8 is operated to make a complete discharge by executing it to a discharge resistor 4, and at the same time, to allow an indication means 6 to represent it by use of a microcomputer 7. The microcomputer 7 suspends the discharge by cutting off the discharge resistor 4 when the output of a voltmeter 3 is lowered to a given value. In this way, it is possible to prevent the memory effect from occurring due to the repetition of slight charge and discharge, and to secure the capacitance of the cell group 2 themselves. Thus, the stabilized driving of a load is assured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery discharge device.

[0002]

2. Description of the Related Art Generally, when a secondary battery such as a nickel-cadmium battery or a nickel-hydrogen battery is deeply discharged after repeating a shallow charge / discharge cycle, the voltage at the time of discharge is 2%.
It is known that a phenomenon called a so-called memory effect of dropping occurs. Therefore, when the memory effect occurs in these secondary batteries used as a power source for various battery devices, the operating voltage of the secondary battery drops by two steps during the operation of the device and suddenly falls below the drive voltage of the device. Problems such as the operation of the device stop. On the other hand, in a battery-driven device such as an 8 mm video camera, when the battery voltage falls below the drive voltage of the device, the battery is electrically disconnected from the device and the operation of the device is stopped. This is to prevent the device from being driven and malfunctioning due to the lowered battery voltage.

By the way, the drive voltage of such equipment is
In many cases, the battery is set to a voltage that does not completely discharge the battery and leaves a reserve capacity. Therefore, when such a charge / discharge cycle is repeated, the memory effect is likely to occur in the battery.
It is also known that this memory effect can be eliminated by performing an appropriate deep discharge during charge / discharge.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to completely discharge a battery after connecting the battery to the device and driving the device so that the memory effect does not occur in the battery. It was done.

[0005]

[Means for Solving the Problems] In the first embodiment,
Battery discharging means, a current detecting means for determining whether the battery is in a conducting state, and a battery discharging switch, the current detecting means determines that the battery is not in a conducting state,
And when the discharge switch is operated, the discharging means discharges the battery.

In the second embodiment, a battery discharging means, a current detecting means for judging whether or not the battery is energized,
The battery voltage detecting means and the timer means operated by the output of the voltage detecting means, the current detecting means determines that the battery is not in the energized state, and the battery voltage is below a predetermined value. When the state detected by the voltage detecting means is measured by the timer means for a predetermined time, the discharging means discharges the battery.

[0007]

According to the first embodiment of the present invention, the current detecting means determines whether or not the battery is energized. That is, when the battery is charged or the connected device is driven, the charging current and the load current are detected and it is determined that the battery is in the energized state. At this time, the discharging means does not discharge the battery. On the other hand, when the charging current or the load current is not detected, it is determined that the battery is not in the energized state and is in the standing state or the standby state. At this time, if the discharge switch is operated, the discharging means starts discharging the battery by utilizing this interval.

Further, according to the second embodiment of the present invention, the current detecting means determines whether or not the battery is energized.
That is, when the battery is charged or the connected device is driven, the charging current and load current are detected,
It is determined that the battery is energized. At this time, the discharging means does not discharge the battery. On the other hand, when the charging current or the load current is not detected, it is determined that the battery is not in the energized state and is in the standing state or the standby state. When the state in which the voltage detecting unit detects that the battery is not in the energized state and the battery voltage is equal to or lower than the predetermined value is counted by the timer unit for a predetermined time, the discharging unit discharges the battery. ..

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail below with reference to the drawings.

The battery discharge device according to the present invention is built in the battery pack 1. That is, the battery pack 1 has a plurality of N
a battery group 2 in which i-Cd batteries are connected in series; a voltage detection means 3 connected to both ends of the battery group 2 to detect a battery voltage;
The discharging means 4 of the battery group 2, the current detecting means 5 connected in series with the battery group 2 to detect the energization state of the battery group 2, and the discharging means 4 indicating that the battery group 2 is being discharged are displayed. Display means 6 for displaying, a microcomputer 7 for outputting operation signals to the discharging means 4, the current detecting means 5, and the displaying means 6 to control the operation of these means, and a discharge switch 8 connected to the microcomputer 7. It consists of The output of the battery pack 1 is selectively connected to a load 9 or a charger (not shown) to drive the load 9 or charge the battery by the charger. A resistor is used as the discharging means 4.

The operation of the battery discharging device in the first embodiment having the above-mentioned structure will be described with reference to the flowchart shown in FIG.

When the battery pack 1 is connected to a charger or the like and is being charged, the current detecting means 5 detects the charging current and outputs a predetermined signal to the microcomputer 7. At this time, the microcomputer 7 determines that the battery group 2 is being charged, and outputs a signal for disconnecting the battery group 2 and the discharging means 4 to the discharging means 4. Therefore, the resistance discharge by the discharge means 4 is not performed. The display means 6 does not display by the signal from the microcomputer 7.

Next, when the battery pack 1 is connected to the load 9 to drive the load, the current detecting means 5 detects the load current and outputs a predetermined signal to the microcomputer 7.
Therefore, as described above, the resistance discharge by the discharging means 4 is not performed.

Next, when the battery pack 1 is neither in the charging state nor in the driving state of the load 9 and the battery voltage detected by the voltage detecting means 3 is below a predetermined value, the microcomputer 7
Receives a signal from the voltage detection means 3 and discharges the discharge means 4
Then, a signal for disconnecting the battery group 2 and the discharging means 4 is output.
Therefore, the resistance discharge by the discharge means 4 is not performed. The display means 6 does not display by the signal from the microcomputer 7. Here, the shut-off voltage of the load 9 used is selected as the predetermined value of the battery voltage.

Next, when the battery voltage is equal to or higher than a predetermined value and the discharge switch 8 is pressed, and the resistance discharge has already been performed by the discharge means 4, the microcomputer 7 causes the discharge means 4 to generate a battery group. A signal for disconnecting 2 from the discharging means 4 is output. Therefore, the resistance discharge by the discharge means 4 is interrupted. The display means 6 does not display by the signal from the microcomputer 7. On the other hand, when the resistance discharge is not performed, the microcomputer 7 outputs a signal for connecting the battery group 2 and the discharge means 4 to the discharge means 4. Therefore, resistance discharge is performed. At this time, the display means 6 also indicates that the resistance discharge is in progress.

The above operation is repeated. Therefore, when the discharge switch 8 is pressed while the resistance discharge is being performed by the discharge means 4, the resistance discharge is interrupted, and when the discharge switch 8 is pressed again, the resistance discharge is restarted. Further, when the resistance discharge progresses and the battery voltage becomes lower than a predetermined value, the resistance discharge ends.

FIG. 3 shows a second embodiment. In this figure, the same circuit parts as those in FIG. 1 are designated by the same reference numerals. The microcomputer 7 in FIG. 3 has timer means built therein. The operation according to the circuit diagram of FIG. 3 is shown in the flowchart of FIG. That is, when the battery pack 1 is connected to a charger or the like and is being charged, the current detecting means 5
Detects the charging current and outputs a predetermined signal to the microcomputer 7. At this time, the microcomputer 7 determines that the battery group 2 is being charged, and outputs a signal for disconnecting the battery group 2 and the discharging means 4 to the discharging means 4. Therefore, the resistance discharge by the discharge means 4 is not performed. The display means 6 does not display by the signal from the microcomputer 7.

Next, when the battery pack 1 is connected to the load 9 to drive the load, the current detecting means 5 detects the load current and outputs a predetermined signal to the microcomputer 7.
Therefore, the resistance discharge by the discharging means 4 is not performed as described above.

Next, when the battery pack 1 is neither in the charging state nor in the driving state of the load 9 and is not in the resistance discharge, the voltage detecting means 3 determines the battery voltage. When the battery voltage is equal to or lower than the predetermined value A, the microcomputer 7 causes the voltage detecting means 3
In response to the signal from, the timer means in the microcomputer 7 is activated. When a predetermined time is measured by the timer means, a signal for connecting the battery group 2 and the discharging means 4 is output to the discharging means 4. Therefore, resistance discharge is performed by the discharge means 4. Further, the display means 6 displays by a signal from the microcomputer 7. Here, the predetermined value A is the load 9 used.
Shut-off voltage of is selected. As described above, the state in which the battery is not in the energized state and the voltage detection unit 3 detects that the battery voltage is equal to or lower than the predetermined value is
When the timer means counts a predetermined time, the discharging means 4 discharges the battery. Next, during resistance discharge,
When the battery voltage eventually drops and the battery voltage falls below the predetermined value B, the resistance discharge ends. As the predetermined value B, a discharge end voltage of 1 V per cell of the battery is selected.

In this embodiment, the battery discharging device is built in the battery pack 1, but the battery discharging device is not limited to this and may be detachably attached to the battery pack as an adapter type.

[0021]

According to the first embodiment of the present invention, a battery discharge means, a current detection means for determining whether or not the battery is energized, and a battery discharge switch are provided. If the current detection means determines that there is not, and the discharge switch is operated, the discharge means discharges the battery.Therefore, when the battery is not used, the discharge switch is operated to discharge the battery. Can be made Further, since the battery will not be discharged unless the discharge switch is operated, it is possible to set the battery in the charger as it is and charge the battery immediately.

According to the second embodiment of the present invention, the battery discharging means, the current detecting means for judging whether or not the battery is energized, the battery voltage detecting means, and the output of the voltage detecting means are operated. The timer means determines a state in which the current detecting means determines that the battery is not in the energized state and the voltage detecting means detects that the battery voltage is below a predetermined value. When timed, the discharging means discharges the battery. Therefore, the battery can be automatically discharged after being used for a load.

As described above, in the battery discharging device according to the present invention, the battery does not have a memory effect, the original capacity of the battery can be secured when the battery is recharged, and stable driving of the load can be guaranteed.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a first embodiment.

FIG. 2 is a flowchart showing the operation in FIG.

FIG. 3 is a block circuit diagram showing a second embodiment.

FIG. 4 is a flowchart showing the operation in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 pack battery 2 battery group 3 voltage detection means 4 discharge means 5 current detection means 6 display means 7 microcomputer 8 discharge switch 9 load

Claims (2)

[Claims] 1. A battery discharging means, a current detecting means for determining whether or not the battery is energized, and a battery discharging switch, wherein the current detecting means judges that the battery is not energized, A discharging device for a battery, wherein the discharging means discharges the battery when the discharging switch is operated. 2. A battery discharging means, a current detecting means for determining whether or not the battery is energized, and a battery voltage detecting means,
A state in which the current detecting means determines that the battery is not in the energized state and the voltage detecting means detects that the battery voltage is below a predetermined value. A discharging device for a battery, wherein the discharging means discharges the battery when the timer means measures a predetermined time.