JPH0834677B2 - Charger - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a secondary battery charging device incorporated in an electric device such as a cordless bar code reader, and particularly to a secondary battery when not in use. The present invention relates to a charging device that sets a charging state.

(Prior Art) For example, in a hand-type bar code reader that optically reads a bar code pattern formed on a product, a bar code reader is used from the viewpoint of facilitating operability and mobility of the bar code pattern. It has a cordless structure that can be separated from a pair of registers or a personal computer. Along with this, the bar code reader has a built-in secondary battery that supplies electric power to a light source for illumination, a light receiving element for reading a bar code pattern, a transmission circuit for transmitting the read bar code information to a register, etc. It

When the barcode reader is made cordless as described above, it is desirable that the barcode reader can be used stably for a long period of time and that it is lightweight.

By the way, it is conceivable to increase the capacity of the secondary battery as a method of using the built-in secondary battery for long-term use of the barcode reader.

However, when the capacity of the secondary battery is increased, the secondary battery becomes large and heavy, and the bar code reader itself also becomes heavy.

Therefore, in order to allow the secondary battery to have a small capacity and light weight and to be used for a long time, a charging device is installed on the dedicated installation base of the barcode reader, and when the barcode reader is not used, it is installed on the exclusive installation base. By doing so, a method is known in which a secondary battery is charged irregularly by a charging device.

(Problems to be Solved by the Invention) However, in the conventional charging method as described above, 2
Since the battery is constantly charged near the upper limit voltage of the secondary battery, it tends to be overcharged, and the internal temperature rises, and the electrodes, separators, etc. are likely to deteriorate. As a result, there is a problem that the life of the secondary battery is shortened.

The present invention has been made in view of the above points, and an object thereof is to provide a charging device capable of improving battery life.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a secondary battery built in an electric device, a detachable installation of the electric device, and a charging input terminal of the rechargeable battery. An installation table having a charging output terminal that is connected and disconnected, a charging power supply unit that is built in the installation table and generates an electric power supplied from the outside to a predetermined charging power, and an installation table that is built in the installation table and includes the secondary battery. When the battery is installed on the installation table, the secondary battery is connected to the secondary battery via the charging input terminal and the charging output terminal, and the secondary battery is charged to a predetermined upper limit voltage by the electric power from the charging power source unit. A charging circuit, a discharging circuit built in the installation table for forcibly discharging the charged electric charge of the secondary battery to a discharge end voltage, and at least a discharging time of a charging time zone and a discharging time zone of the secondary battery. Set the band periodically And a rechargeable circuit for charging the secondary battery of the electric device installed on the installation table via the charging input terminal and the charging output terminal each time the discharging time zone set by the timer means arrives. From the discharge circuit to the discharge circuit, and switch means for forcibly discharging the charge charged in the secondary battery.

Further, in the present invention, the discharge circuit includes a monitoring unit that detects a discharge end voltage of the secondary battery, and the monitoring unit has two units.
When the discharge end voltage of the secondary battery is detected, the switch means is switched from the discharge circuit to the charge circuit and connected even during the discharge time zone set by the timer means.

In the present invention, the charging power source is a backup power source unit that generates another external power source such as AC for charging, and the backup power source when the regular external power supply to the charging power source is down. It is equipped with a switching means for switching to.

Further, according to the present invention, the charging circuit detects a connection and an opening between a charging input terminal of the secondary battery and a charging output terminal of the installation base, and the detecting means detects the charging input terminal and the charging output. A switch means is provided which is turned on when the connection with the terminal is detected to supply the charging current to the secondary battery, and is turned off when the opening of the charging output terminal is detected to cut off the charging current to the secondary battery. It will be.

(Operation) When the discharge time zone set by the timer means is reached, the switch means is switched to the discharge circuit side to forcibly discharge the charge stored in the secondary battery to the discharge end voltage. This improves the charge / discharge cycle life of the secondary battery.

Further, when the monitoring means detects the end-of-discharge voltage of the secondary battery, the switch means is switched to the charging circuit side for recharging even though the timer means is in the discharge time zone. This prevents the secondary battery from being over-discharged.

Furthermore, when the regular external power supply is down, the backup power supply operates to operate the charging circuit and the discharging circuit normally. This ensures that the secondary battery is charged and discharged.

When the output terminal of the charging circuit is opened due to the use of the electric device, the switch means in the charging circuit is turned off so that no voltage is applied to the output end of the charging circuit. As a result, even if a conductor piece or the like contacts the output end of the charging circuit,
Prevent the charging circuit from being short-circuited or burnt out.

(Example) Hereinafter, the Example of this invention is described based on drawing.

1 to 3 are a first embodiment showing a case where the charging device according to the present invention is applied to charging a secondary battery of a bar code reader, and FIG. 1 is an overall configuration diagram, FIG. Is a charge / discharge circuit diagram, and FIG. 3 is an output waveform diagram.

First, in FIG. 1, reference numeral 1 is a cordless separation type bar code reader, which includes an illuminating light source 2 including an infrared light emitting diode, a light source driving circuit 3, and a bar code label BL illuminated by the illuminating light source 2. A light receiving element 5 such as a CCD that receives reflected light of the light through the condenser lens 4, an amplifier circuit 6 that amplifies an analog signal output from the light receiving element 5, and an output signal of the amplifier circuit 6 is compared with a reference voltage. , That big,
A waveform shaping circuit 7 for converting a binary signal according to the smallness, an arithmetic processing circuit 8 for converting a binary signal from the waveform shaping circuit 7 into bar code information, and an output signal from the arithmetic processing circuit 8. And a transmission circuit 9 for converting into an optical signal and transmitting.

10 is a secondary battery composed of nickel-cadmium storage battery, etc., which is a light source driving circuit 3, a light receiving element 5, an amplifying circuit 6, a waveform shaping circuit.
7, which supplies electric power to the arithmetic processing circuit 8 and the transmission circuit 9, and the secondary battery 10 is also incorporated in the barcode reader 1.

 Reference numerals 11a and 11b are input terminals for charging the secondary battery 10.

Denoted at 13 is a dedicated installation base on which the barcode reader 1 is detachably installed. In the dedicated installation base 13, a power supply unit 14 for generating a DC voltage for charging and a power supply unit 14 for charging are used. And a charging circuit 15 for charging the secondary battery 10 to a predetermined voltage,
In the discharge circuit 16 that forcibly discharges the secondary battery 10 to the end-of-discharge voltage, the switch circuit 17 that switches the secondary battery 10 to the charging circuit 15 and the discharge circuit 16, and at the time when the barcode reader 1 is not used, such as at night. A 24-hour timer 18 is provided to switch and connect the switch circuit 17 to the discharge circuit 16 side and control to connect the other time zone to the charge circuit 15 side.

Reference numerals 19a and 19b denote charging output terminals that are separated from and contact with the charging input terminals 11a and 11b on the side of the barcode reader 1, and are provided in the recess 13a for engaging the barcode reader of the dedicated installation table 13. The one output terminal 19a is directly connected to the charging circuit 15 and the discharging circuit 16, and the other output terminal 19b is switchably connected to the charging circuit 15 and the discharging circuit 16 by the switch circuit 17.

 Next, the circuit configuration of FIG. 2 will be described.

In FIG. 2, the charging power supply unit 14 includes a booster circuit 14a, which is a register or a central computer (hereinafter, referred to as a signal processing main body) on the barcode information receiving side of the barcode reader 1. ) Is to convert the voltage of 5V supplied from 8V to the voltage required for charging.

The charging circuit 15 keeps the current from the booster circuit 14a constant (about 500
constant current circuit 15a for controlling the charging current supplied to the secondary battery 10 from the constant current circuit 15a through the charging output terminals 19a, 19b from the constant current circuit 15a.
(Constituting switch means), monitoring the terminal voltage of the secondary battery 10 and detecting the opening of the charging output terminals 19a, 19b, and depending on the terminal voltage level of the secondary battery and the presence / absence of release of the output terminal. It is composed of a window comparator 15c (which constitutes a monitoring means and a detection means) for controlling on / off of the analog switch 15b.

The constant current circuit 15a includes transistors Q1 and Q2, a zener diode ZD and resistors R1 and R2, and the analog switch 15b is a P-channel MOS transistor.
It is composed of Q3, a resistor R3 connected between the source and gate of the MOS transistor Q3, an npn transistor Q4 connected between the gate of the MOS transistor Q3 and ground, and a resistor R4.

Further, the window comparator 15c is a secondary battery 10
The resistors R5 and R6 that detect the terminal voltage of and the voltage across the resistor R6 divided by the resistors R5 and R6 are used as the input of the inverting input terminal.
Also, the voltage across the first oven collector type comparator OP1 and the resistor R6, which uses the reference voltage V _rH as the input of the non-inverting input terminal, is the input of the non-inverting input terminal, and the reference voltage V _rL is the input of the inverting input terminal. And a second open collector type comparator OP2.

The discharging circuit 16 uses the discharging resistor 16a connected to the charging output terminals 19a and 19b through the contact b of the switch circuit 17 and the terminal voltage of the secondary battery 10 as the input of the inverting input terminal, and also the reference voltage V A comparator 16b that monitors the discharge end voltage of the secondary battery 10 by using _L (corresponding to the discharge end voltage) as the input of the non-inverting input terminal and the output signal of the 24-hour timer 18 as the D input, and the output signal of the comparator 16b D for clock input
-Flip-flop 16c, NAND that outputs the output of the D-flip-flop 16c and the output signal of the 24-hour timer 18 as two inputs
It is composed of a gate 16d.

The switch circuit 17 is composed of a transistor 17a which is on / off controlled by an output signal of the NAND gate 16d, and a relay 17b connected to the collector of the transistor 17a. The switching contact 17b1 of the relay 17b connects the charging output terminals 19a and 19b to the output end of the charging circuit 15 and the discharging circuit 16.
The switch is connected to the input terminal of.

Next, the third embodiment of the operation of the present embodiment configured as described above will be described.
Description will be made with reference to the waveform charts shown in the figures.

First, it is assumed that the bar code reader 1 is installed on the dedicated installation base 13 and the charging input terminals 11a and 11b thereof are connected to the charging output terminals 19a and 19b of the dedicated installation base 13.

At this time, if the bar code reader 1 is in a time zone such as daytime when it is relatively frequently used, the output signal of the 24-hour timer 18 becomes "L" level as shown in FIG. 3 (c). Therefore, the output of the NAND gate 16d becomes "H" level as shown in FIG. 3 (d) by the "L" output of the 24-hour timer 18 and the "H" output of the D-flip-flop 6c.

As a result, the transistor 17a of the switch circuit 17 is turned on and the relay 17b is energized.
1 is connected to the contact a side.

In this state, if the terminal voltage of the secondary battery 10 is lower than the charging upper limit voltage V _H at time t _{1 in} FIG. 3 (a), it is obtained by dividing the voltage with resistors R5 and R6 of the window comparator 15c. The input voltage to the comparator OP1 is the reference voltage V _rH
Since it falls further, the output of the comparator OP1 becomes "H" level as shown in FIG. 3 (b).

As a result, the transistor Q4 of the analog switch 15b is turned on, and the gate voltage of the MOS transistor Q3 is "L".
It goes to level and the MOS transistor Q3 turns on.

As a result, the constant current from the constant current circuit 15a is applied to the MOS transistor Q3, the contact a of the switching contact 17b1 and the output terminal 19 for charging.
Flows to the secondary battery 10 through a, 19b and input terminals 11a, 11b, 2
Charging for the next cell 10 to the upper limit voltage V _H.

When the terminal voltage of the secondary battery 10 reaches the charging upper limit voltage V _H at time t _{2 in} FIG. 3 (a), the output of the comparator OP1 is inverted to the “L” level, the transistor Q4 is turned off, and the MO transistor is turned on.
The gate of the S transistor Q3 is set to "H" level to turn off the MOS transistor Q3. That is, the charging of the secondary battery 10 is stopped.

When the bar code reader 1 is left set on the dedicated installation base 13, the terminal voltage of the secondary battery 10 does not change at all, but at the time of t _{3 in} FIG. When it is separated from the dedicated installation base 13 to use the code reader 1,
Since the charging output terminals 19a and 19b are opened, the constant current circuit 1
The current from 5a flows through the MOS transistor Q3 to the resistors R5 and R6 of the window comparator 15c.

As a result, the voltage generated at the connection point a with the resistors R5 and R6 becomes V _rH or more shown by the broken line in FIG. 3 (a), so that the logical output of the comparator OP2 also becomes “L” and the analog switch 15b becomes Turn off. As a result, the voltage at the output terminals 19a and 19b of the charging circuit 15 becomes zero as shown in FIG. 3 (a).

That is, when the charging output terminals 19a and 19b of the dedicated installation base 13 are opened, the input voltage of the window comparator 15c becomes zero and becomes equal to or lower than the reference voltage _{VrL of} the comparator OP2, so that the output of the comparator OP2 becomes "L". "It will be a level.

As a result, the output of the window comparator 15c is "L".
Therefore, the transistor Q4 of the analog switch 15b turns off, and the MOS transistor Q3 also turns off.

When the MOS transistor Q3 is turned off, the charging output terminal 1
Since 9a and 19b are electrically disconnected from the charging circuit 15, the charging output terminals 19a and 19b are in an inactive state.

As a result, even if a conductor piece or the like contacts between the charging terminals 19a and 19b placed in the open state, the discharging circuit, especially the constant current circuit.
There is no risk of element damage such as short circuiting of 15a.

Next, when the reading of the bar code pattern by the bar code reader 1 is completed and the bar code reader 1 is installed again on the dedicated installation base 13 at time t _{4 in} FIG. When the terminal voltage of the secondary battery 10 is judged and the terminal voltage is at the upper limit voltage V _H , the state is maintained as it is, and when it is lower than the upper limit voltage V _H as shown in FIG. 3 (a). , The analog switch 15b is turned on again to charge the secondary battery 10.

Thereafter, in the same manner as above, the secondary battery 10 is charged as shown in FIG. 3 (a) by repeating the above-described operation during the usage time of the barcode reader 1.

On the other hand, when the bar code reader 1 is not used, such as at night, when the time set in advance by the 24-hour timer 18 is reached, the output of the 24-hour timer 18 becomes "H" as shown in FIG. 3 (c). "Invert to level.

Along with this, the NAND gate 16d which receives the "H" output of the 24-hour timer 18 and the "H" output of the D-flip-flop 16c as inputs
Since the logic output of is at "L" level, transistor 17a
Is turned off, and the relay 17b is deenergized, and its switching contact 17b
Connect 1 to switch to contact b side.

As a result, the secondary battery 10 of the bar code reader 1 installed on the dedicated installation table 13 is connected to the discharge circuit 16, and the secondary battery 10 inside the secondary battery 10 from the time point t ₅ when the 24-hour timer 18 is inverted to the “H” level. Is discharged through the discharge resistor 16a until the discharge end voltage V _L is reached.

At this time, for example, if the capacity until the voltage of the secondary battery 10 drops to 60% is 100 mAh and the discharge current is 100 mA,
The discharge end voltage V _L is reached in about 1 hour.

Therefore, the output of the 24-hour timer 18 is inverted to the "L" level after about 1 hour has passed from the time point t _5, and the relay 17b of the switch circuit 17 is activated again to switch the secondary battery 10 to the charging circuit 15. The secondary battery 10 is charged again to the upper limit voltage V _H.

On the other hand, while the output of the 24-hour timer 18 is "H", the comparator 16b monitors the terminal voltage of the secondary battery 10.

Therefore, when the comparator 16b detects that the terminal voltage of the secondary battery 10 has reached the discharge end voltage _VL , its output becomes "H", and the D-flip-flop 16c receives the D-flip-flop 16c as a clock. Invert the output of the 16c from "H" to "L".

As a result, even if the output of the 24-hour timer 18 is "H", 2
When the terminal voltage of the secondary battery 10 reaches the discharge end voltage V _L , NAND
The logic output of the gate 16d is "H" as shown in FIG. 3 (d).
Since the level is reached, the relay 17b of the switch circuit 17 is energized and the secondary battery 10 is forcibly connected to the charging circuit 15 to be charged.

In the present embodiment as described above, it is set to 2 during the non-use time period of the bar code reader 1 which is predetermined by the 24-hour timer 18.
Since the next cell 10 was manner to discharge once a day until the discharge end voltage V _L is switched to the discharge circuit 16 side of the switching circuit 17, the conventional manner always method which repeatedly charges near the upper limit voltage V _H In comparison, the secondary battery 10 does not become overcharged or the internal temperature does not rise, and the deterioration of the electrodes or the separator is reduced accordingly.
The life of the secondary battery can be significantly improved.

For example, in a secondary battery in which the number of charge / discharge cycles from the upper limit voltage V _H to the discharge end voltage V _L is specified to be 500,
Conventionally, it had a cycle life of about 300 times, but can be charged and discharged up to the specified 500 times or more.

Further, when the secondary battery 10 is discharged, its terminal voltage is monitored by the comparator 16b, and if the terminal voltage of the secondary battery 10 reaches the discharge end voltage V _L within the discharging time set by the 24-hour timer 18, 2 Since the secondary battery 10 is forcibly switched to the discharge circuit 15 to be charged, over-discharge of the secondary battery 10 can be prevented.

Further, when the bar code reader 1 is not used during the usage time, the secondary battery 10 is installed on the dedicated installation base 13 so that the secondary battery 10 can be repeatedly charged. Therefore, the secondary battery 10 can have a smaller capacity. Accordingly, the weight of the secondary battery 10 and the weight of the bar code reader can be reduced and downsized.

Furthermore, when the bar code reader 1 is separated from the dedicated installation base 13, the opening of the charging output terminals 19a, 19b is detected by the window comparator 15c, and thereby the switch circuit 15b is turned off to output the output terminals 19a, 19b. Since no voltage is applied, even if a conductor piece or the like contacts the output terminals 19a, 19b, the discharge circuit 16 is not short-circuited or burned, and safety can be ensured.

Next, a second embodiment of the present invention will be described with reference to FIGS.

In this embodiment, a function of backing up the charging / discharging circuit when the power of the signal processing main body is turned off is added. FIG. 4 is an overall configuration diagram, FIG. 5 is a circuit configuration diagram of a charging power supply unit, FIG. 6 is the time chart.

First, in FIG. 4, the charging circuit 15, the discharging circuit 16, the switching circuit 17, the 24-hour timer 18, and the features of the present embodiment are provided on the dedicated installation base 13 of the bar code reader 1 as in the case shown in FIG. A charging power source 14A, which is a portion, is provided.
Further, 19a and 19b are charging output terminals provided in the recess 13a of the dedicated installation base 13.

The charging power source 14A is a booster circuit 14a as shown in FIG.
And the DC voltage (5 V or 12 V
A relay 20 for switching and connecting the power source for V) and backup to the booster circuit 14a, and a rectifier circuit 21 for converting AC 100V AC into DC of a predetermined voltage.

The relay 20 includes an exciting coil 20a connected to a DC input terminal 22 from the signal processing body, and switching contacts 20b and 20c for switching and connecting the DC input terminal 22 from the signal processing body and the output end of the rectifier circuit 21 to the booster circuit 14a. , And switching contacts 20d, 20e for switching and connecting the input end of the rectifier circuit 21 to the AC input terminal 23.
It consists of

The rectifier circuit 21 includes a transformer 21a for stepping down AC100V to a predetermined voltage, a diode bridge 21b for full-wave rectifying the secondary output of the transformer 21a, and a capacitor 21c for smoothing the DC output of the diode bridge 21b. It consists of and.

The DC input terminal 22 and a signal processing body (not shown) are connected by a power supply cord 24, and the AC input terminal 23 and an AC power supply are connected by a power supply cord 25.

Next, the operation will be described with reference to the time chart of FIG.

First, when the main power supply on the signal processing main body side is alive without being interrupted, a DC voltage (for example, 5V) from the signal processing main body is applied to the DC input terminal 22 of the charging power supply unit 14A through the power supply cord 24. Has been.

At this time, since the exciting coil 20a of the relay 20 is excited, its switching contacts 20b and 20c are normally open side contacts.
It is connected to a ₁ and a ₂ , and the switching contacts 20d and 20e are also connected to the normally open side contacts a ₃ and a ₄ .

As a result, the DC voltage V ₁ from the signal processing
The boosted voltage (for example, 8V) supplied to the booster circuit 14a through 20b and 20c is output to the charging circuit 15 as in the case shown in FIGS. 1 and 2 to charge the secondary battery 10. become.

Moreover, since the input side of the rectifier circuit 21 is opened by the switching contacts 20d and 20e, the DC voltage V ₂ is not generated at the output side of the rectifier circuit 20.

On the other hand, when the main power supply of the signal processing unit is turned off during a non-use time such as at night, the DC voltage V ₁ applied to the DC input terminal 22 at that time t ₁ becomes zero as shown in FIG. 6 (a), Along with this, the exciting coil 20a of the relay 20 is also demagnetized.

As a result, the switching contact 20b, 20c, 20d.20e is connected is switched to the fifth normally closed side contact b _1, as shown in _{FIG, b 2, b 3, b} 4. In this switching state, the rectifier circuit 20
Since the input side of is connected to the AC input terminal 23, and the output side thereof is connected to the booster circuit 14a, the DC output voltage V ₂ of the rectifier circuit 21 changes the switching contacts 20b, 20c as shown in FIG. 6 (b).
Will be supplied to the booster circuit 14a through.

That is, when the main power supply of the signal processing main body is turned off, the power supply to the charging circuit 15 is backed up by supplying the DC voltage V ₂ obtained from the AC power supply of another system through the rectifier circuit 21 to the charging power supply unit 14A. Then, the secondary battery 10 can be charged by the barcode reader, and at the same time, the secondary battery 10 can be forcibly discharged.

Incidentally, in FIG. 6, FIG. 6 (c) shows the waveform of the current flowing through the exciting coil 20a, and FIG. 6 (d) shows the operating state of each contact of the relay 20.

In the second embodiment, unlike the first embodiment, power can be supplied to the charging power supply unit 14A even when the main power supply of the signal processing main body is cut off, and the barcode reader In addition to being able to charge the secondary battery 10, the secondary battery 10
The operation of forcibly discharging the charged electric charge of to the discharge end voltage V _L can be surely performed.

In the first embodiment described above, the case where the window comparator is used to determine whether the bar code reader 1 is installed on the dedicated installation table 13 has been described.
Not limited to this, for example, a Hall element may be provided on the dedicated installation table 13 and a magnet may be provided on the bar code reader 1 side, and further, a limit switch may be provided on the dedicated installation table,
The presence or absence of a bar code reader may be detected.

In addition, in the second embodiment described above, the case where the discharge circuit 16, the switch circuit 17, and the 24-hour timer 18 are added to the dedicated installation table 13 has been described, but the present invention is not limited to this, and only the charging circuit 15 is provided. Needless to say, the charging power source system shown in the second embodiment can also be applied.

Further, the present invention is not limited to the separate type bar code reader shown in the embodiments, but it goes without saying that the present invention can be applied to other electric devices having a built-in secondary battery as the cordless type is realized.

(Effects of the Invention) As described above, according to the present invention, there is provided timer means for periodically setting at least the discharging time zone of the charging time zone and the discharging time zone of the secondary battery, and the timer means sets the timer. By controlling the switch means every time the discharged discharge time period arrives, the secondary battery of the electric device installed on the installation stand is switched from the charging circuit to the discharging circuit and connected.
Since the configuration is such that the charge of the secondary battery is forcibly discharged, the secondary battery can be discharged periodically regardless of the terminal voltage, and as a result, electrical equipment is installed on the installation table for a long time. Even if the battery is left unattended, it prevents the rechargeable battery from overcharging and prevents the internal temperature from rising and the electrodes or separators inside the rechargeable battery from deteriorating. Can be greatly improved.

Further, according to the present invention, a monitoring means for detecting the discharge end voltage of the secondary battery is added to the discharge circuit.
When the secondary battery is forcibly discharged regularly because the switch means is switched from the discharge circuit to the charging circuit even when the discharge end voltage of the secondary battery is detected, even during the discharge time period set by the timer means. It is possible to prevent the secondary battery from being over-discharged below the discharge end voltage.

According to the present invention, the charging power source is a backup power source unit that generates another external power source such as AC for charging,
Since the switching means for switching to the backup power supply when the regular external power supply for the charging power supply is down, the regular power supply is cut off when the main power supply such as the signal processing main body is turned off during a non-use time such as at night. Even if the external power supply is down, there is an effect that the charging circuit and the discharging circuit can be normally operated to reliably charge and discharge the secondary battery.

Further, according to the present invention, the charging circuit has a detection means for detecting connection and disconnection between the charging input terminal of the secondary battery and the charging output terminal of the installation base, and the detecting means has the charging input terminal and the charging output terminal. When the connection is detected, it is turned on to supply the charging current to the secondary battery, and when detecting the opening of the charging output terminal, it is turned off to cut off the charging current to the secondary battery. Even if a conductor piece or the like comes into contact with the charged charging output terminal to cause a short circuit between the charging output terminals, it is possible to prevent the charging circuit from being short-circuited or burned out.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of the present invention, FIG. 2 is a circuit diagram showing a concrete example of a charging device in the first embodiment, and FIGS. 3 (a) to 3 (d) are FIG. 4 is a waveform diagram for explaining the operation, FIG. 4 is a configuration diagram showing a second embodiment of the present invention, and FIG.
FIG. 6 is a circuit diagram of a charging power source section according to the second embodiment,
The figure is the time chart. In the figure, 1 is a bar code reader, 10 is a secondary battery, 11
a, 11b are input terminals for charging, 13 is a dedicated installation stand, 14 and 14A are power sources for charging, 15 is a charging circuit, 15a is a constant current circuit, 15b is an analog switch, 15c is a window comparator, 16 is a discharging circuit, 16a is a discharge resistor, 16b is a discharge end voltage monitoring comparator, 17 is a switch circuit, 18 is a 24-hour timer, 20
Is a relay and 21 is a rectifier circuit.

Claims (4)

[Claims] 1. A rechargeable battery built into an electric device, an installation base on which the electric device is removably installed, and a charging output terminal that separates from and connects to a charging input terminal of the rechargeable battery; A charging power supply unit that is built-in and that generates power supplied from the outside to a predetermined charging power; and a charging battery that is built in the installation base and that installs the secondary battery on the installation base and charges the secondary battery. A charging circuit connected via an input terminal and a charging output terminal for charging the secondary battery to a predetermined upper limit voltage with electric power from the charging power source unit; A discharge circuit for forcibly discharging the charged electric charge of the secondary battery up to the discharge end voltage; timer means for periodically setting at least the discharge time zone of the charge time zone and the discharge time zone of the secondary battery; Set The secondary battery of the electric device installed on the installation table is switched and connected from the charging circuit to the discharging circuit via the charging input terminal and the charging output terminal each time the power hours arrive. A charging device comprising: a switch unit for forcibly discharging the charge of the battery. 2. The discharge circuit comprises a monitoring means for detecting the discharge end voltage of the secondary battery, and when the monitor means detects the discharge end voltage of the secondary battery, the discharge set by the timer means. 2. The charging device according to claim 1, wherein the switching means is switched from the discharging circuit to the charging circuit even during a time zone. 3. The charging power source is a backup power source unit for generating another external power source such as AC for charging, and the backup power source when the regular external power source for the charging power source is down. The charging device according to claim 1, further comprising switching means for switching. 4. The charging circuit includes a detecting unit for detecting connection and disconnection between a charging input terminal of the secondary battery and a charging output terminal of the installation table, and the detecting unit having the charging input terminal and the charging output terminal. A switch means is provided which is turned on when a connection to the battery is detected and supplies a charging current to the secondary battery, and is turned off when an opening of the charging output terminal is detected to cut off the charging current to the secondary battery. 1. The charging device according to 1.