JPH0722070A - Charge and discharge device - Google Patents

Abstract

PURPOSE:To charge and discharge a battery while the battery is mounted in a main body case and to facilitate switching by providing the main body case with a power plug for connection to a charge circuit in such a way as to be freely pulled in and out, and charging or discharging the battery according to the pulling-in or -out of the plug. CONSTITUTION:A battery mounting portion 2 is provided by recessing of the front side of a main body case 1, and a secondary battery 3 is removably mounted therein. A terminal portion corresponding to the exposed electrode portion of the battery 3 is provided on the inner peripheral surface of the mounting portion 2, and the exposed electrode portion of the battery 3 is connected to the terminal portion when the battery 3 is mounted. A power plug 4 comprises a pair of plug blades 4a supported inside a storage recessed portion 5 in such a manner as to be freely rotating about a pivot 4b, the storage recessed portion 5 being provided in the upper portion of the rear side of the case 1. A blade 4a is turned relative to the rear side of the case so that the plug 4 is freely pulled in and out. A charge circuit 6 and a discharge circuit 7 are enclosed in the case 1, and when the plug 4 is pulled out the circuit 6 is connected to the battery 3, whereas when the plug 4 is pulled in the circuit 6 is switched to the circuit 7 by a switch circuit 13. The battery 3 can thus be charged and discharged while being mounted, and switching is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging / discharging device for charging or discharging a secondary battery, which is a power source in portable electronic equipment such as video cameras, personal computers, cordless telephones and the like.

[0002]

2. Description of the Related Art Secondary batteries such as nickel-cadmium batteries have been widely used as power sources in portable electronic devices because they can be used repeatedly by recharging even after being discharged once.

A charging device for charging this type of secondary battery is
Usually, a constant current circuit for converting a commercial AC power source into a desired DC output and outputting the same, a charging voltage detection circuit for detecting a voltage between both terminals of a secondary battery, that is, a charging voltage, and a charging operation controlled based on the charging voltage. It is composed of a charge control circuit and the like.

By the way, this type of secondary battery to be charged, especially a nickel-cadmium battery, is ideally recharged when it is completely used up, and when shallow charging and discharging are repeated, There may occur a phenomenon in which the charging voltage suddenly drops during charging, or a so-called memory phenomenon in which the battery itself stores its capacity and is not completely discharged.

Therefore, conventionally, a discharger for forcibly discharging the secondary battery before charging has been used so that the performance of the secondary battery can always be maximized.

[0006]

However, when the above-mentioned discharger is used for charging the secondary battery, the secondary battery is attached to the discharger to discharge, and then the secondary battery is removed from the discharger. This time, it is necessary to attach this to the charger, which is a complicated work, and it is very troublesome to perform this work each time the rechargeable battery that is repeatedly used is charged.

The present invention has been made in view of the above problems of the prior art, and its object is to perform a discharging operation and a charging operation with a secondary battery attached. Moreover, it is another object of the present invention to provide a charging / discharging device that can switch between a discharging operation and a charging operation very easily.

[0008]

In order to achieve the above object, in the charging / discharging device of the present invention, a secondary battery is mounted in a battery mounting portion provided in a main body case, and the secondary battery is charged or charged. A charging / discharging device for discharging, in which a charging circuit and a discharging circuit are mounted in a main body case, a power plug connected to the charging circuit is provided in the main body case in a retractable manner, and the charging circuit is provided when the power plug protrudes. A switch circuit is provided for connecting to the secondary battery and connecting the secondary battery to the discharge circuit when the power plug is immersed.

[0009]

In the charging / discharging device having the above-described structure, when the secondary battery is mounted in the main body case and the power plug provided in the main body case is immersed, the switch circuit is connected to the discharge circuit side and the secondary circuit is connected. The battery discharges according to the function defined in the discharge circuit.

On the other hand, when the power plug is projected during charging of the secondary battery, the switch circuit is connected to the charging circuit side, and when the power plug is connected to the commercial AC power source, the power is supplied to the charging circuit and the secondary battery is supplied. Charging operation is performed.

[0011]

EXAMPLES Examples will be described with reference to FIGS. 1 to 5.

First, FIG. 1 shows the appearance of a charging / discharging device, in which a battery mounting portion 2 is recessed on the front surface of a main body case 1 made of resin molding or the like, and a secondary battery 3 made of a nickel-cadmium battery is provided therein. Is detachably attached. The inner peripheral surface of the battery mounting portion 2 is provided with a terminal portion corresponding to the exposed electrode portion of the secondary battery 3, and when the secondary battery 3 is mounted, the exposed electrode portion of the secondary battery 3 is the terminal portion. Connected to.

A power plug 4 connected to a commercial AC power source, that is, a household power outlet is provided on the upper rear surface of the body case 1.
Is provided so that it can appear and disappear freely. As shown in FIGS. 3 and 4, the power plug 4 has a pair of plug blades 4a rotatably supported by a pivot shaft 4b in a storage recess 5 provided in the upper rear surface of the main body case 1. The power plug 4 can be retracted and retracted by rotating both plug blades 4a so as to tilt up and down with respect to the rear surface of the body case 1.

As shown in FIG. 2, a charging circuit 6 for mainly charging the secondary battery 3 and a discharging circuit 7 for discharging the secondary battery 3 are housed inside the main body case 1.

The charging circuit 6 is a constant current circuit that converts the commercial AC power source 8 connected to the power plug 4 into a desired DC output and outputs the desired DC output. A charging voltage that detects the voltage across the secondary battery 3, that is, the charging voltage. It has a detection circuit, a charging control circuit for controlling the charging operation based on the charging voltage, and the like.

The charging control circuit performs an operation of stopping the charging operation when the battery voltage reaches a peak voltage and then drops by a predetermined voltage. Alternatively, instead of stopping the charging operation, trickle charging is performed for a set time and the charging operation is stopped.

The discharge circuit 7 includes a discharge load such as a resistor and 2
It has a discharge voltage detection circuit that detects the voltage across the secondary battery 3, that is, the discharge voltage, a discharge control circuit that controls the discharge operation based on the discharge voltage, and the like.

The discharge control circuit performs the discharging operation when the battery voltage is lower than the specified voltage lower than the rated voltage and stops the discharging operation when the battery voltage is lower than the discharge completion voltage lower than the specified voltage.

The charging voltage detecting circuit and the discharging voltage detecting circuit are constituted by a common battery voltage detecting circuit, and the secondary battery 3
The charging voltage or the discharging voltage may be shared for detection.

In the charging circuit 6, a charging indicator lamp 9 which is turned on during the charging operation by the charging control circuit is provided with a current limiting resistor 10.
Connected through. Further, the discharge circuit 7 is connected through a current limiting resistor 12 with a discharge indicator lamp 11 that lights up during a discharge operation by the discharge control circuit and blinks for a certain period of time when the battery voltage is equal to or lower than the discharge completion voltage.

These charge indicator lamp 9 and discharge indicator lamp 11
Is arranged, for example, on the front surface of the main body case 1.

The charging circuit 6 and the discharging circuit 7 are connected to the secondary battery 3 via switch circuits 13, respectively. The switch circuit 13 includes a charging circuit 6 and a secondary battery 3
Charging side contact 14 interposed between the discharging circuit 7 and 2
The discharge side contact 15 is interposed between the secondary battery 3 and the secondary battery 3, and these are constituted by mechanical contacts as shown in FIGS. 3 and 4, and each contact is operated by one plug blade 4a of the power plug 4. .

That is, the two contacts 14, 15 are respectively the main contact pieces 14b, 15 supported by the insulating supports 14a, 15a.
It is composed of b and movable contact pieces 14c and 15c that face each other in parallel. The movable contact pieces 14c, 15c and the main contact piece 14
b and 15b are composed of conductive leaf springs, and the movable contact piece 1
4c and 15c are formed slightly longer than the main contact pieces 14b and 15b. An operation piece 16 is provided on the base of the one plug blade 4a so as to project into the main body case 1 through a guide hole 17 in the inner wall of the storage recess 5.

Here, the charging side contact 14 is the operation piece 1 of the plug blade 4a when the power plug 4 projects rearward.
The movable contact piece 14c is pressed by 6 and this is the main contact piece 14c.
It is arranged at a position in contact with b. The discharge side contact 15 is arranged at a position where the movable contact piece 15c is pressed by the operation piece 16 of the plug blade 4a when the power plug 4 is housed in the housing recess 5 and is brought into contact with the main contact piece 15b. There is.

A reverse current blocking diode 18 is connected between the charging circuit 6 and the switch circuit 13.

FIG. 5 shows the voltage characteristics of the secondary battery 3 and the operation characteristics of the charging indicator lamp 9 during the charging operation, and the charging operation will be described with reference to the figure.

The secondary battery 3 is attached to the battery mounting portion 2 of the main body case 1.
As shown in FIG. 3, the power plug 4 is projected from the main body case 1 and plugged into a household power outlet, the commercial AC power source 8 is connected to the charging circuit 6, and the plug blade 4a The charging side contact 14 is turned on by the operation piece 16 and the secondary battery 3 is connected to the charging circuit 6 via the switch circuit 13 and the diode 18.

Therefore, the AC output of the commercial AC power supply 8 is converted into a desired DC output in the charging circuit 6 and output.
This is 2 via the diode 18 and the switch circuit 13.
It is supplied to the secondary battery 3 and the charging operation of the secondary battery 3 is started (at t ₁ ). At this time, the charging indicator 6 is charged by the charging circuit 6.
Is driven to light.

As the charging operation progresses, the battery voltage gradually rises, and the charging control circuit in the charging circuit 6 continues the charging operation while detecting the peak value of the battery voltage. The peak voltage is detected, for example, by sampling the battery voltage in a certain cycle and the battery voltage detected this time becomes lower than the battery voltage detected last time.

Then, when the peak voltage is detected at t ₂ after the battery voltage reaches the rated voltage V ₀ of the secondary battery 3, the charging control circuit causes the battery voltage to exceed the peak voltage by a predetermined voltage Δ.
The charging operation is continued until V decreases, and at t ₃ when the decrease in the predetermined voltage ΔV is detected, the charging control circuit stops the charging operation,
At the same time, the charging indicator lamp is also controlled to be turned off.

Thereafter, the power plug 4 is unplugged from the outlet, and the power plug 4 is housed in the housing recess 5 with the secondary battery 3 still attached to the main body case 1. While being turned off,
This time, the discharge side contact 15 is operated by the operation piece 16 of the plug blade 4a.
Is turned on, and the secondary battery 3 is connected to the discharge circuit 7 via the switch circuit 13.

However, the discharge control circuit of the discharge circuit 7 is
Since the battery does not operate unless the battery voltage is lower than the specified voltage V _{1 which} is lower than the rated voltage V ₀ , the discharging operation is not performed even if the secondary battery 3 is still attached to the main body case 1. .

FIG. 6 shows the voltage characteristics of the secondary battery 3 and the operation characteristics of the discharge indicator lamp 11 during the discharge operation, and the discharge operation will be described with reference to the figure.

The secondary battery 3 having a reduced capacity is used as the main body case 1
When the power plug 4 is mounted in the battery mounting portion 2 and the power plug 4 is stored in the storage recess 5, the operation piece 16 of the plug blade 4a is
Causes the discharge side contact 15 to be turned on, and the secondary battery 3 is connected to the discharge circuit 7 via the switch circuit 13.
When the battery voltage of the secondary battery 3 is higher than the specified voltage V ₁ , the discharging operation is not performed as described above.

When the battery voltage becomes equal to or lower than the specified voltage V ₁ , the discharge control circuit of the discharge circuit 7 connects the secondary battery 3 to the discharging load and the discharging operation is started (at t ₄ ). At this time, the discharge indicator lamp 11 is driven to light up by the discharge circuit 7.

As the discharge operation progresses, the battery voltage gradually decreases, and the discharge control circuit in the discharge circuit 7 continues the discharge operation until the battery voltage reaches the discharge completion voltage V ₂ lower than the specified voltage V ₁ .

When the battery voltage drops below the discharge completion voltage V ₂ at t ₅ , the discharge control circuit disconnects the discharging load from the secondary battery 3 and stops the discharging operation. at the same time,
The discharge circuit stops continuous lighting of the discharge indicator lamp 11 and switches to blinking operation.

Therefore, by blinking the discharge indicator lamp 11, it is possible to notify the user of the completion of the discharge operation with good visibility, and it is possible to prompt the shift to the charging operation.
Flashing operation of the discharge indicator 11 is carried out for a certain time in the sense of preventing over-discharge of the secondary battery 3, at a subsequent t _6, the driving of the discharge display lamp 11 is completely stopped.

The present invention is not limited to the above-mentioned embodiment, and it is obvious that the present invention can be modified without departing from the gist of the present invention.

For example, the power supply plug provided in the main body case may be of a slide type, and the power supply plug may be slidable into and out of the main body case. In this case, the switch circuit corresponds to the sliding position of the power supply plug. Therefore, the charging circuit side and the discharging circuit side may be switched.

Further, the switch circuit is not limited to the leaf spring-like contact piece described above, but may have another contact structure, and detects the retracted state of the power plug at the rotational position of the pivot shaft supporting the plug blade. You may do it.

[0042]

Since the present invention is configured as described above, it has the following effects. In the charging / discharging device according to claim 1, the switch circuit is connected to the discharge circuit side by immersing the power plug provided in the main body case, and the secondary battery mounted in the main body case is appropriately discharged. In addition to projecting the power plug when charging the secondary battery, the switch circuit is connected to the charging circuit side, and commercial AC power connected to the power plug is supplied to the charging circuit to charge the secondary battery. Since the secondary battery is attached to the main body case, the discharging operation and the charging operation can be performed, and the discharging operation and the charging operation can be switched between charging and discharging, that is, the power plug can be retracted. At the same time, there is an effect that the switching operation is very easy.

Moreover, since the secondary battery can be discharged once and then charged when charging the secondary battery, the performance and life of the secondary battery are not deteriorated.
It is possible to maximize the performance of the secondary battery.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a charging / discharging device according to the present invention.

FIG. 2 is a circuit diagram of the charging / discharging device of the present invention.

FIG. 3 is an enlarged cross-sectional view of the accommodating portion of the power plug shown in FIG. 1 during charging.

FIG. 4 is an enlarged cross-sectional view of the accommodating portion of the power plug shown in FIG. 1 during discharging.

FIG. 5 is a voltage characteristic diagram during a charging operation of the present invention.

FIG. 6 is a voltage characteristic diagram during discharge operation of the present invention.

[Explanation of symbols]

 1 Body Case 3 Secondary Battery 4 Power Plug 6 Charging Circuit 7 Discharging Circuit 8 Commercial AC Power Supply 9 Charging Indicator Light 11 Discharge Indicator Light 13 Switch Circuit

Claims (7)

[Claims] 1. The battery mounting portion provided on the main body case is provided with 2
A charging / discharging device for mounting a secondary battery and charging or discharging the secondary battery, wherein a charging circuit and a discharging circuit are mounted in the main body case, and the main body case is connected to the charging circuit. A power plug is provided so as to be retractable, and a switch circuit is provided for connecting the charging circuit to the secondary battery when the power plug is projected and connecting the secondary battery to the discharging circuit when the power plug is retracted. Characteristic charging / discharging device. 2. The charging circuit includes a constant current circuit, a battery voltage detection circuit, and a charging control circuit, and the charging control circuit stops the charging operation when the battery voltage drops by a predetermined voltage after reaching the peak voltage. The charging / discharging device according to claim 1. 3. The charging / discharging device according to claim 2, wherein the charging circuit is connected to a charging indicator lamp that lights up during a charging operation. 4. The discharge circuit includes a discharge load, a battery voltage detection circuit, and a discharge control circuit, and the discharge control circuit performs a discharge operation when the battery voltage is equal to or lower than a specified voltage lower than a rated voltage. 1. The charging / discharging device according to 1. 5. The charging / discharging device according to claim 4, wherein the discharge control circuit stops the discharging operation when the battery voltage is equal to or lower than the discharge completion voltage lower than the specified voltage. 6. The charging / discharging device according to claim 4, wherein the discharge circuit is connected to a discharge indicator lamp that is turned on during a discharging operation. 7. The charging / discharging device according to claim 5, wherein the discharge indicator lamp is lit during the discharging operation and blinks for a certain period of time when the battery voltage is equal to or lower than the discharge completion voltage.