JPH06178457A - Charging apparatus - Google Patents

Abstract

PURPOSE:To charge a secondary battery of a first kind and a second kind by discriminating whether the secondary battery is of the first kind or of the second kind. CONSTITUTION:Whether a secondary battery E is of a first kind or of a second kind is discriminated by a battery-kind discrimination means 36. When the secondary battery E is discriminated to be of the first kind, it is continued that constant-current charging voltages from charging-voltage generation circuits 8, 17, 19 are supplied to the secondary battery E until the secondary battery E is charged fully. When the secondary battery E is discriminated to be of the second kind, the charging-voltage generation circuits 8, 17, 19 are controlled when it is detected by a battery-voltage detection circuit 16 that the voltage of the secondary battery E has exceeded a reference voltage according to the secondary battery E, its charging voltages are changed over from the constant- current charging voltages to constant-voltage charging voltages, and its charging operation is continued. Thereby, the secondary battery, of the first kind, which is charged by a constant current only and the secondary battery, of the second kind, which is charged by a constant current at the beginning and by a constant voltage after that can be charged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device capable of charging secondary batteries of different trees.

[0002]

2. Description of the Related Art When a secondary battery is charged, it must be charged with a charging voltage having characteristics according to its type. In the case of a nickel-cadmium battery, charging must be performed with a constant-current charging voltage as shown in FIG. 2, but in the case of a lithium-ion battery, initially with a constant-current charging voltage, as shown in FIG. When the voltage of the battery reaches a predetermined reference voltage corresponding to the battery, the charging voltage must be switched to a constant voltage for charging.

[0003]

However, there are conventional charging devices for exclusive use of nickel-cadmium batteries and those for exclusive use of lithium-ion batteries, and a charging device that can charge both of these batteries is not available. It has never been before.

In view of the above, the present invention provides a first type of secondary battery which is charged only by constant current charging and a second type which is initially charged by constant current charging and then by constant voltage charging. The present invention is intended to propose a charging device capable of charging the secondary battery of.

[0005]

SUMMARY OF THE INVENTION The present invention is a secondary battery of the first type that is charged only by constant current charging and a second type of battery that is initially charged by constant current charging and then by constant voltage charging. The charging device is capable of charging various types of secondary batteries. The charging device includes charging voltage generating circuits 8, 17, and 19 for selectively generating a constant current and a constant voltage charging voltage, and charging voltage generating circuits 8, 17, and 1.
When the full-charge of the secondary battery E is detected, the shut-off switch 26 that shuts off the supply of the charging voltage from the secondary battery E to the secondary battery E is controlled, and the shut-off switch 26 is controlled to charge the voltage generation circuits 8, 17, 19 Full-charge detection circuit 9, 10, 11, 12, 16 for shutting off the supply of the charging voltage to the secondary battery E from
And when the voltage of the secondary battery E exceeds a reference voltage corresponding to the secondary battery E, this is detected and the charging voltage generation circuit 8,
The battery voltage detection circuits 13, 14, 15 for controlling the charging voltage of the constant current generated after the start of charging to the charging voltage of the constant voltage by controlling 17, 19 and the first and the second of the secondary battery E. A battery type discriminating means 36 for discriminating between the two types,
When the battery type determination means 36 determines that the secondary battery E is the first type secondary battery, the charging voltage generation circuits 8 and 17 based on the detection outputs of the battery voltage detection circuits 13, 14 and 15. , 19 to prevent switching from the constant current charging voltage to the constant voltage charging voltage, and when it is determined that the secondary battery E is the second type secondary battery, The switching from the charging voltage to the constant voltage is allowed.

[0006]

According to the present invention described above, when the full charge detection circuits 9, 10, 11, 12, 16 detect the full charge of the secondary battery E, the charge voltage generation circuits 8, 17, 1 are generated.
9 is controlled to stop the generation of the charging voltage. The battery type determination unit 36 determines whether the secondary battery E is the first type secondary battery or the second type secondary battery. When it is determined that the secondary battery E is the secondary battery of the first type, the charging voltage of the constant current from the charging voltage generating circuits 8, 17, 19 is kept until the secondary battery E is fully charged. Continues to be common to the secondary battery E. Secondary battery E is second
If the battery voltage detection circuit 16 detects that the voltage of the secondary battery E exceeds the reference voltage corresponding to the secondary battery E, , Controlling the charging voltage generation circuits 8, 17, 19
The charging voltage is switched from the constant current charging voltage to the constant voltage charging voltage to continue charging.

[0007]

Embodiments of the present invention will be described in detail below with reference to FIG. E is a secondary battery as a charging target,
Either the first type of secondary battery, ie, NiCd battery, or the second type, ie, lithium ion secondary battery, in which a plurality of secondary batteries are accommodated in a pack (accommodation body) 34a. The secondary battery pack 34 is configured. in this case,
For example, when the secondary battery E is a nickel-cadmium battery, the protrusion 35 is provided in the housing 34a, and when the secondary battery E is a lithium-ion battery, the protrusion 35 is omitted. Note that this may be reversed. Further, the type of the secondary battery E is distinguished by changing the position, the number, the shape, etc. of the protrusions provided in the housing 34a, changing the position, the number, the shape, etc. of the recess, or changing the bar code. can do. In the case of a bar code, it may be directly attached to the secondary battery.

The presence or absence of the protrusion 35 of the container 34a is detected by the switch 36 provided in the battery container of the charging device. When the protrusion 35 is present, the switch 36 is turned on, and when not present, it is turned off.

The regulator 8 and its output terminal OUT
The resistor 17 serially connected to the above constitutes a charging voltage generating circuit for charging the secondary battery E. Regulator 8
Is a constant voltage generating circuit, and as an example, the input / output terminal I
An NPN transistor 8a having a collector and an emitter connected between N and OUT, a resistor 8b connected between the collector and the base, and a cathode and an anode connected between the base of the transistor 8a and the ground terminal GND, respectively. Zener diode (constant voltage element) 8
It is composed of c. In addition, a resistor 17 having a resistance value sufficiently larger than the internal resistance of the secondary battery E is connected in series to the output terminal OUT of the regulator 8, whereby the current flowing in the secondary battery E is made constant.

Next, a circuit for obtaining the DC voltage supplied to the regulator 8 will be described. A commercial AC power supply is connected to the primary coil of the transformer 2 via the power switch 1. The middle point of the secondary coil of the transformer 2 is grounded, and both ends thereof are connected to the anode of the rectifying diode 3 and the cathode of the diode 4, respectively. The cathode of the diode 3 and the anode of the diode 4 are respectively smoothing capacitors 5, It is grounded through 6 and is directly connected to the regulator 7, and the regulator 7 provides DC voltages of + V ₀ and -V ₀ , respectively. Then, the DC voltage having the voltage of + V ₀ is supplied to the regulator 8.

The output terminal OUT of the regulator 8 is connected in series with the resistor 17 and the switch 26 of the relay 25, is connected to the anode of the backflow prevention diode 24, and its cathode is connected to the positive electrode of the secondary battery E. The negative electrode of the secondary battery E is grounded. A switch 19 of a relay 18 is connected in parallel with the resistor 17.

Next, after a lapse of a predetermined time from the start of charging the secondary battery E, the switch 26 is turned off to shut off the supply of the charging voltage from the regulator 8 to the secondary battery. (Timer circuit) will be described. The more positive voltage + V _{0 of the} regulator 7 is applied to the relay coil 27 of the relay 25 and the collector-emitter series circuit of the transistor 28. Positive voltage of regulator 7 + V
₀ is supplied to the series circuit of the resistor 9 and the capacitor 10 and the series circuit of the resistors 11 and 12. The voltage V _{2 at} the connection midpoint between the resistor 9 and the capacitor 10 is supplied to the non-inverting input terminal of the level comparator 16, and the voltage V _{3 at} the connection midpoint between the resistors 11 and 12 is supplied to the level comparator 16.
It is supplied to the inverting input terminal of. In addition, this level comparator 1
6 includes positive and negative voltages + V ₀ and −V from the regulator 7.
₀ is supplied as the operating voltage. The output terminal of the level comparator 16 is connected to the transistor 28 through the resistor 33.
Supplied to the base of.

A discharging resistor may be connected in parallel with the capacitor 10.

When the power switch 1 is turned on, the resistor 1
Voltage V at the midpoint of connection between 1 and 12₃Immediately becomes a predetermined voltage
Is the voltage V at the midpoint of the connection between the resistor 9 and the capacitor 10.₂
Gradually increases from 0V. And of the power switch 1
V after input₂<V₃Therefore, the output voltage of the level comparator 16
The pressure becomes low level (ground level), and the transistor 28
Is off and no current flows through the coil 27 of the relay 25.
Yes. Therefore, the switch 26 is in the break state (ON).
The charging voltage from the regulator 8 is supplied to the secondary battery E.
To be done. Then, the resistance value of the resistor 9 and the capacitor 10
For example, 60 minutes have elapsed according to the time constant determined by the capacity of
Then, the voltage V₂, V₃Relationship is V₂> V ₃And this
As a result, the output voltage of the level comparator 16 becomes high level.
Then, the transistor 28 is turned on, and the relay 25
A current flows through the switch 27 and the switch 26 is turned off.
Of the charging voltage from the regulator 8 to the secondary battery E
Supply is cut off.

The full charge detection circuit having a timer structure can also be used as a timer by a microcomputer.

Next, switching of the charging voltage characteristic from the charging voltage generating circuit composed of the regulator 8 and the resistor 17 will be described depending on whether the secondary battery E is a nicad battery or a lithium ion battery. . The positive voltage + V ₀ from the regulator 7 is supplied to the coil 20 of the relay 18 and the series circuit between the collector and emitter of the transistor 29. The positive voltage + V ₀ from the regulator 7 is connected to the coil 23 of the relay 21 and the series circuit between the collector and emitter of the transistor 31. The ground terminal GND of the regulator 8 is connected to the movable contact of the switch 22 of the relay 21, one of the fixed contacts is grounded, and the other fixed contact is connected to the connection midpoint of the resistor 17 and the switches 19 and 26. It The positive voltage + V ₀ of the regulator 7 is supplied to the series circuit of the resistors 13 and 14, and the voltage V _{4 at} the connection midpoint of the resistors 13 and 14 is supplied to the inverting input terminal of the level comparator 15, and The voltage at the connection midpoint of the resistor 17 and the switches 19 and 26, that is, the voltage V ₅ of the secondary battery E is supplied to the non-inverting input terminal of the level comparator 15.

When the secondary battery E is a nickel cadmium battery, the switch 36 is turned on because the protrusion 35 is provided on the housing 34a. Therefore, the transistor 2
Both 9 and 31 are turned off, no current flows through the coils 20 and 23 of the relays 18 and 21, the switch 19 of the relay 18 is in the break state (off), and the switch 2 of the relay 21 is
2 is in a break state (the movable contact is connected to the fixed contact on the resistor 17 side). For this reason, the voltage V ₁ between the output terminal OUT of the regulator 8 and the ground terminal GND is divided by the resistance value R ₁ of the resistor 17, and the constant current charging voltage of V ₁ / R ₁ = i is the secondary battery (NiCd battery). ) E (see FIG. 2). As described above, 60 minutes after the power switch 1 is turned on, the switch 26 of the relay 25 is turned off and the charging is stopped.

If the secondary battery E is a lithium ion battery, the switch 36 is off because the protrusion 35 is not provided in the housing 34a. Therefore, the voltage V _{5 of the} secondary battery (lithium ion battery) E is the reference voltage V
_When V ₅ <V ₄ lower than ₄ , the output voltage of the level comparator 15 becomes a low level, that is, the ground voltage, the transistors 29 and 31 are both turned off, and the coils 20 and 23 of the relays 18 and 21 are turned off. No current flows through the relay 18, the switch 19 of the relay 18 is in the break state (OFF), and the switch 22 of the relay 21 is in the break state (the movable contact is connected to the fixed contact on the resistor 17 side). Therefore, the regulator 8
The voltage V ₁ between the output terminal OUT and the ground terminal GND of V is divided by the resistance value R ₁ of the resistor 17 and the constant current charging voltage of V ₁ / R ₁ = i is supplied to the secondary battery (lithium ion battery) E. (See FIG. 3).

After that, when the voltage V ₅ of the secondary battery E rises and becomes V ₅ > V ₄ , the output voltage of the level comparator 15 becomes high level, the transistors 29 and 31 are both turned on, and the relay is turned on. A current flows through each coil 20, 23 of 18, 21, and the switch 19 of the relay 18 is in the make state (ON),
The switch 22 of the relay 21 is in the make state (the movable contact is connected to the fixed contact on the ground side). Therefore, the constant-voltage charging voltage from the regulator 8 is supplied to the secondary battery E. When the voltage V ₅ of the secondary battery E becomes V ₅ = V ₄ , the secondary battery E is charged to about 70% of the full charge. In the constant voltage charging region, the internal impedance of the secondary battery E apparently rises, so that the charging current gradually decreases (see FIG. 3). As mentioned above,
60 minutes after the power switch 1 is turned on, the switch 26 of the relay 25 is turned off and the charging is stopped.

The voltage per battery differs depending on the type of the secondary battery to be charged (for example, 1.2V for NiCad battery and 3.6V for lithium ion battery), the charging characteristics are different, and the batteries are connected in series. Since the number of
The charging voltage or the charging current may be switched based on the determination of the type of the next battery.

An electronic switch may be used instead of the relays 18, 21 and 25 described above.

[0022]

According to the present invention described above, a secondary battery of the first type that is charged only by constant current charging and a second battery that is initially charged by constant current charging and then by constant voltage charging. It is possible to obtain a charging device capable of charging a type of secondary battery.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a curve diagram showing an example of charging characteristics of a nickel-cadmium battery.

FIG. 3 is a curve diagram showing an example of charging characteristics of a lithium ion battery.

[Explanation of symbols]

 8 Regulator 9 Time Constant Circuit Resistor 10 Time Constant Circuit Capacitor 11 Resistor Divider Resistor 12 Resistor Divider Resistor 13 Resistive Divider Resistor 14 Resistor Divider Resistor 15 Level Comparator 16 Level Comparison Unit 17 Charging voltage generator resistor 18 Relay 19 Relay 18 switch 20 Relay 18 coil 21 Relay 22 Relay 21 switch 23 Relay 21 coil 24 Backflow prevention diode 25 Relay 26 Relay 25 switch 27 Relay 25 coil 28 Switching transistor 29 Switching transistor 31 Switching transistor E Secondary battery 34 Secondary battery pack 34a Storage body (pack) 35 Protrusion 36 Switch

Claims (4)

[Claims] 1. Charging for a first type of secondary battery that is charged only by constant current charging and for a second type of secondary battery that is initially charged by constant current charging and then by constant voltage charging. A charging device capable of performing the above-mentioned 2) by selectively generating a constant current and a constant voltage charging voltage.
A charging voltage generating circuit to be supplied to the secondary battery, an interruption switch for interrupting the supply of the charging voltage from the charging voltage generating circuit to the secondary battery, and the interruption switch when full charging of the secondary battery is detected. A full charge detection circuit for controlling the supply of the charging voltage from the charging voltage generating circuit to the secondary battery by controlling the voltage of the secondary battery when the voltage of the secondary battery exceeds a reference voltage corresponding to the secondary battery. A battery voltage detection circuit that detects this and controls the charging voltage generation circuit to switch the charging voltage of the constant current generated after the start of charging to the charging voltage of the constant voltage; and the secondary battery. Battery type discriminating means for discriminating between the first and second types, and the secondary battery is the first type by the battery type discriminating means.
When it is determined that the battery is a secondary battery of the above type, the constant voltage charging voltage generated by the charging voltage generating circuit is switched to the constant voltage charging voltage by the detection output of the battery voltage detecting circuit. In addition to blocking, when it is determined that the secondary battery is the secondary battery of the second type, switching from the constant current charging voltage to the constant voltage charging voltage is allowed. A charging device characterized in that. 2. The charging device according to claim 1, wherein the battery type determining means is a switch. 3. The distinction between the first and second types of the secondary battery is the presence / absence of a protrusion provided in a housing body housing the secondary battery. The charging device according to 2. 4. The charging device according to claim 1, wherein switching of the constant current and the constant voltage of the charging voltage of the charging voltage generating circuit is performed by a relay switch.