JPH08140281A - Charger - Google Patents

Abstract

PURPOSE: To activate a chargeable battery device being overdischarged, and pull up the output voltage so as to enable quick charging by arranging the constitution such that the quick discharging is performed when the charging voltage of the chargeable battery device reaches the voltage capable of quick charging. CONSTITUTION: A charging control microcomputer 2 starts the charging, and turns off a quick charging ON/OFF switch circuit 1 so as to perform preliminary charging, and turns on a preliminary charging ON/OFF switch circuit 6. And, a charging control microcomputer 2 reads the output voltage of a charging battery device 4 through an AD converter 10, and if t is not less than the voltage with which the charging control microcomputer 2 can operate, the charging control microcomputer 2 turns off the preliminary charging ON/OFF switch circuit 6 and turns on the quick charging ON/OFF switch circuit 1 so as to perform quick charging until the output voltage of the chargeable battery device 4 becomes stable. Hereby, the chargeable battery device 4 overdischarged can be activated, and it can be quickly charged, with output increased.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, portable electronic devices with a built-in battery, such as personal computers, word processors, video cameras, facsimiles, and mobile phones, have become widespread. Where these electronic devices can use a commercial power source, the electronic device main body is operated by the commercial power source. If commercial power is not available, use rechargeable battery power. When the voltage of the rechargeable battery drops, the operation of the electronic device main body is stopped and the charging circuit built in the device is charged, or the battery is removed and charging is performed by an external charger. Further, since it takes time to charge with the standard charging current of the rechargeable battery used, a current several to several tens of times higher than the standard charging current is flowed to perform rapid charging in a short time.

Generally, a rechargeable battery often suffers a short circuit damage when it deteriorates due to aging, and even if it does not operate, a slight leakage current flows, so if it is left for a long time, a deep discharge occurs and the output voltage drops. There is a nature to say.
When such a rechargeable battery is rapidly charged, there is a problem in that the output voltage is considerably lower than the discharge end voltage or a short circuit occurs and the load is heavy and cannot be charged. An example is shown below.

FIG. 11 shows an example of the configuration of a conventional battery charger. In the figure, 1 is a rapid charge ON / OFF switch circuit, 2 is a charge control microprocessor (hereinafter abbreviated as charge control microcomputer), 10 is an A / D converter, 3 is power supply to the charge control microcomputer 2 and A / D converter 10. A constant voltage power supply device for supplying 12, a cell 4, a rechargeable battery device in which a plurality of cells 12 of constant current charging type such as a nickel-cadmium storage battery and a nickel-hydrogen storage battery are connected in series. An example in which the cells 12 are connected in series will be described. An external power supply device 5 functions as a constant current power supply during rapid charging and as a constant voltage power supply when driving the electronic device body 13.

At the time of rapid charging, for example, charging is performed with a current corresponding to a charging rate of 1C to 2C. Here, C is a charging rate, for example, a rechargeable battery device 4 having a capacity of 1200 mAh.
Then, 1C means charging with a current of 1200mA, 2C means charging with 2400mA, and 1 / 2C means charging with 600mA. Reference numeral 9 is a main electronic circuit portion of the electronic device (for example, a CPU circuit or I / O peripheral circuit in the case of a computer), and 13 is an electronic device main body.

Next, FIG. 12 shows a flow chart of charge control executed by the charge control microcomputer 2 of the conventional battery charger. The operation will be described with reference to this figure. In step 1 in FIG. 12, when the power of the external power supply device 5 is turned on, a power switch (not shown) of the electronic device main body 13
When is turned off, the charging control microcomputer 2 detects it and starts charging. In step 2, charge control microcomputer 2
Quick charge ON / OFF switch circuit 1 to charge
Control to turn on.

The time from the start of charging until the output voltage of the rechargeable battery device 4 stabilizes, for example, after charging for 3 minutes, the process proceeds to step 3, where the charge control microcomputer 2 outputs the output voltage of the rechargeable battery device 4. To A / D converter 1
It is read through 0, and it is determined whether the rechargeable battery device 4 includes the short-circuited cell 12 based on the output voltage (for example, 8 V or more). Generally, the short-circuited cell 12 cannot be charged at an output voltage of 0 v, so if the output voltage is less than 8 v, 1 out of 6
If more than one cell 12 is short-circuited, it is determined that there is a short-circuited cell 12, and the process proceeds to step 7, where charging is determined to be abnormal and charging is stopped. If it is 8 v or more, the process proceeds to step 4 and it is determined whether the rechargeable battery device 4 is fully charged. If the battery is fully charged, the process proceeds to step 5, where the charging is considered normal and the charging is stopped. If not fully charged, proceed to step 6 and continue rapid charging to step 3
Return to

Depending on the type of the rechargeable battery, the method of terminating the charging when the voltage of the rechargeable battery device 4 rises and reaches a specified voltage, or when the voltage continues to rise and then drops, is used as the determination of full charge. End charging- △ V method,
There is also a method of detecting an increase in storage battery temperature and ending charging. The above operation is the case where the charge control microcomputer 2 can operate normally, and if all the cells 12 included in the rechargeable battery device 4 are in a deep discharge or short-circuit state, the output voltage of the rechargeable battery device 4 becomes 0v or 0v. The voltage will be close.

Then, when the charging control microcomputer 2 is rapidly charged, the charging control microcomputer 2 passes through the constant voltage power source 3 and
Since the power is taken from the same external power supply device 5 as the rechargeable battery device 4, the supplied voltage drops to the same voltage as the output voltage of the rechargeable battery device 4. Therefore, the charge control microcomputer 2 cannot operate. Then, the hardware autonomously turns off the rapid charging ON / OFF switch circuit 1. As a result, the rapid charging current does not flow, the load is lightened, and the charging control microcomputer 2 can operate. In addition, when the charge control microcomputer 2 is rapidly charged, the supplied voltage drops to the same voltage as the output voltage of the rechargeable battery device 4, and the charge control microcomputer 2 becomes inoperable, which is repeated.

[0010]

When the rechargeable battery device 4 including the deep-discharged or short-circuited cells 12 is rapidly charged as in the above-described conventional example, the charge control microcomputer 2 repeats inoperability / recovery, resulting in rapid operation. Charging will be performed intermittently, and the normal cell 1 built in the rechargeable battery device 4 will be charged.
If there is 2, there was a problem of being overcharged. There is a problem that the rechargeable battery device 4 cannot be charged because the output voltage drops because the rechargeable battery device 4 is left for a long time or is deeply discharged, and the charge control microcomputer 2 cannot control the charging.

The present invention has been made to solve the above problems, and a first object thereof is to provide a rechargeable battery device 4 whose output voltage is lowered due to being left for a long time or deeply discharged. The purpose is to activate and raise the output voltage to enable rapid charging.

A second object of the present invention is to prevent the charge control microcomputer 2 from being out of control and from being repeatedly restored due to a heavy load of a rechargeable battery device which is deeply discharged or short-circuited during rapid charging.

A third object of the present invention is to provide a charging device which can reduce thermal stress and can use parts having a small mounting space.

A fourth object is to detect early whether or not the rechargeable battery device incorporates a short-circuited cell.

[0015]

According to a first aspect of the present invention, there is provided a charging device for charging a rechargeable battery device with a current larger than a self-discharge current and smaller than a standard charging current according to the capacity of the rechargeable battery device. Charging means, quick charging means for charging the rechargeable battery device with a current larger than the standard charging current according to the capacity of the rechargeable battery device, predetermined reference voltage and charging voltage of the rechargeable battery device And a precharging means for charging, and a comparing means for comparing the reference voltage with the charging voltage of the rechargeable battery device. If the charging voltage is higher than the reference voltage, the quick charging means performs rapid charging. Charging control means for controlling.

In the charging device according to the second aspect of the invention, the charging control means charges the preliminary charging means, and after a predetermined time, the comparing means compares the reference voltage with the charging voltage of the rechargeable battery device. If the voltage is lower than the voltage, a means for stopping the charging is provided.

According to a third aspect of the present invention, there is provided a charging device in which precharging means for charging with a standard charging current according to the capacity of the rechargeable battery device and a current larger than the standard charging current according to the capacity of the rechargeable battery device. With a quick charging means for charging the rechargeable battery device with a predetermined time, a voltage that can be reached by a normal rechargeable battery device that cannot be reached by a rechargeable battery device including a short-circuited cell is used as a reference voltage, and this reference voltage is used. And the charging voltage of the rechargeable battery device are compared with each other, and after a predetermined time, the comparing device compares the reference voltage with the charging voltage of the rechargeable battery device, and the charging voltage is the reference voltage. If it is lower, charging is stopped, and if it is higher, charging control means for controlling to be charged by the quick charging means is provided.

In the charging device according to the fourth aspect of the present invention, the precharging means includes a resistance element.

In the charging device according to the fifth aspect of the present invention, the precharging means includes a field effect transistor having a gate to which a constant voltage is applied.

In the charging device according to the sixth aspect of the invention, the precharging means has a constant current circuit.

In the charging device according to the seventh aspect of the present invention, the pre-charging means and the charge control means control the field-effect transistor for supplying the pre-charging current or the rapid charging current and the field-effect transistor for causing the rapid charging current to flow. It is provided with one switching element and a second switching element for controlling the field effect transistor so as to flow a current for pre-charging.

A charging device according to an eighth aspect of the present invention controls a quick charging means for charging the rechargeable battery device with a current larger than a standard charging current according to the capacity of the rechargeable battery device and a quick charging means. And a power supply means for supplying power from the rechargeable battery device to the charge control means.

[0023]

According to the first aspect of the invention, the precharging means charges the rechargeable battery device with a current that is larger than the self-discharge current and smaller than the standard charge current according to the capacity of the rechargeable battery device. Further, the quick charging means charges the rechargeable battery device with a current larger than the standard charging current according to the capacity of the rechargeable battery device. The comparing means compares a predetermined reference voltage determined in advance with the charging voltage of the rechargeable battery device. Then, the charging control means performs charging by the preliminary charging means, compares the reference voltage with the charging voltage of the rechargeable battery device by the comparing means, and if the charging voltage is higher than the reference voltage, controls the quick charging means to perform rapid charging. To do.

In the second invention, the charge control means is
The pre-charging means charges the battery, and after a predetermined time, the comparing means compares the reference voltage with the charging voltage of the rechargeable battery device. If the charging voltage is lower than the reference voltage, the charging is controlled to stop.

In the third aspect of the invention, the pre-charging means charges with a standard charging current according to the capacity of the rechargeable battery device. Further, the quick charging means charges the rechargeable battery device with a current larger than the standard charging current according to the capacity of the rechargeable battery device. The comparison means charges the battery for a predetermined time, reaches a normal rechargeable battery device, and does not reach a rechargeable battery device including a short-circuited cell as a reference voltage, and the reference voltage and the charging voltage of the rechargeable battery device are compared with each other. To compare. Then, the charging control means performs charging by the preliminary charging means, compares the reference voltage with the charging voltage of the rechargeable battery device by the comparing means after a predetermined time, and stops the charging if the charging voltage is lower than the reference voltage, and increases the charging voltage. Then, control is performed so that charging is performed by the quick charging means.

In the fourth aspect of the invention, the precharging means causes a charging current to flow through the resistance element.

In the fifth aspect of the invention, the pre-charging means causes the field effect transistor in which a constant voltage is applied to the gate to flow the charging current.

In the sixth aspect of the invention, the precharging means causes the constant current circuit to flow the charging current.

In the seventh invention, the field effect transistor causes the current for pre-charging or the current for rapid charging to flow. Then, the first switching element controls the field-effect transistor so that a rapid charging current flows, and the second switching element controls the field-effect transistor so that a preliminary charging current flows.

In the eighth invention, the quick charging means charges the rechargeable battery device with a current larger than the standard charging current according to the capacity of the rechargeable battery device. Then, the charging control means controls to charge by the quick charging means. Further, the power supply means supplies power from the rechargeable battery device to the charge control means.

[0031]

【Example】

Example 1. If the short-circuit or deep-discharge rechargeable battery device 4 is suddenly and rapidly charged, the power supply cannot drive the charge control microcomputer 2 due to a heavy load. Therefore, in this embodiment, the capacity of the power supply is not increased, and an inactive rechargeable battery is not used. Device 4
Is charged with a light load current that can activate the
When the charging voltage rises and the voltage becomes operable even if the mode is switched to the rapid charging, the rapid charging is attempted.

The pre-charging before the rapid charging of the rechargeable battery device 4 is performed at a standard charging ratio (1 / 10C, which is higher than the charging ratio capable of activating the inactive rechargeable battery device 4, for example, the self-discharge ratio). In the range of 1 / 15C to 1 / 7C)
Charging is performed at a charging current of 40 mA to 60 mA for the rechargeable battery device 4 having a capacity of 1200 mAh with a smaller current determined by the charging rate of 1/30 C to 1/20 C. Then, by reducing the pre-charging current, small components with low power consumption are used in the pre-charging circuit to obtain a small charging device.

Then, during the pre-charging, the charge control microcomputer 2
Determines whether the charging voltage of the rechargeable battery device 4 has reached a predetermined voltage (for example, 6v or higher), and if it has reached the predetermined voltage (6v or higher), rapid charging is performed. However, this predetermined voltage is the rechargeable battery device 4
If the charging voltage of 1 has reached this value, the charging control microcomputer 2 is set to a voltage at which the charging control microcomputer 2 can operate normally even if the charging is switched to rapid charging. Hereinafter, this predetermined voltage is referred to as an operable voltage of the charge control microcomputer 2. It should be noted that this voltage is determined by the operating voltage of the elements forming the charge control microcomputer 2.

An embodiment according to the present invention is shown in FIG. FIG. 1 is different from FIG. 11 of the conventional example in that a precharge ON / OFF switch circuit 6 and a precharge circuit 7 for performing precharge are added. In the figure, 6 is ON / O for preliminary charging
FF switch circuit, 7 is a pre-charging circuit for pre-charging,
Others are the same as the conventional example and the description thereof is omitted. The external power supply device 5 works as a constant current source during rapid charging with a heavy load,
The rapid charging current and the power of the constant voltage power supply device 3 are supplied. It functions as a constant voltage source during preliminary charging with a light load, and supplies the preliminary charging current and the constant voltage power supply 3 as a power source. The constant voltage power supply 3 includes a charge control microcomputer 2 and an A / D converter 10
Supply the power of.

FIG. 2 shows a flowchart of the charging control executed by the charging control microcomputer 2 in these configurations.
FIG. 2 is different from FIG. 12 of the conventional example in that a step of performing preliminary charging and a step of determining whether the output voltage of the rechargeable battery device 4 is 6 V or more are added. In the figure, the charge control microcomputer 2 starts charging in step 1, the charge control microcomputer 2 turns off the quick charge ON / OFF switch circuit 1 and turns on the preliminary charge ON / OFF switch circuit 6 so that the charge control microcomputer 2 performs precharge in step 2. To control.

Then, in step 3, the output voltage of the rechargeable battery device 4 is read by the charging control microcomputer 2 via the A / D converter 10, and it is judged whether the operating voltage of the charging control microcomputer 2 is, for example, 6 v or more. If so, go back to step 2 to continue precharging. If it is 6v or more, the process proceeds to step 4 and the charging control microcomputer 2 turns on the preliminary charging ON / OF.
The F switch circuit 6 is turned off and the rapid charge ON / OFF switch circuit 1 is controlled to be turned on, and rapid charging is performed until the output voltage of the rechargeable battery device 4 stabilizes, for example, 3 minutes. Then, the process proceeds to step 5, and the rechargeable battery device 4
The charging control microcomputer 2 controls the output voltage of the A / D converter 1
It is read through 0 and it is determined whether the output voltage is a voltage that cannot be reached by charging if the rechargeable battery device 4 includes the short-circuited cell 12. For example, in the case of six cells 12 connected in series as in the conventional example, the presence or absence of a short-circuited cell is determined depending on whether the output voltage is 8 v or higher. Steps 6 and 7 below
Steps 8 and 9 are the same as steps 4, 5, 6 and 7 of the conventional example shown in FIG.

As described above, the charging control microcomputer 2 determines during the preliminary charging whether the output voltage of the rechargeable battery device 4 is a voltage at which the charging control microcomputer 2 can operate even when performing rapid charging. If it can be operated, rapid charging will be performed.
It does not quickly charge heavy loads.

Further, since the charge control microcomputer 2 performs preliminary charging with a small current with a light load before the chargeable battery device 4 is rapidly charged, the output voltage drops due to deep discharge. 4 can be charged and the charging voltage can be raised to the operable voltage of the charging control microcomputer 2. However, the short-circuited cell cannot be charged, but the charge control microcomputer 2 should be used so that a heavy load is not applied by quick charging.
The charging control microcomputer 2 does not stop operating. In addition, the normal rechargeable battery device 4 can be rapidly charged immediately after preliminary charging. Furthermore, since the pre-charging is performed with a weak current, a small component with low power consumption can be used in the pre-charging circuit.

Next, an example in which the precharge circuit 7 is composed of a resistor will be shown. FIG. 3 shows that the external power supply device 5 of FIG.
A path for charging the rechargeable battery device 4 via the N / OFF switch circuit 6 and the preliminary charging circuit 7 is shown, and an example in which the preliminary charging circuit 7 is constituted by the resistor R is shown. The output voltage of the external power supply device 5 is V0, the output voltage of the rechargeable battery device 4 is Vb, the resistance value is R, and the resistance value R
Compared with the internal resistance of the external power supply device 5 and precharge ON / OF
Assuming that the ON resistance of the F switch circuit 6 is very small, the charging current flowing through the rechargeable battery device 4 is (Vo-V
b) / R.

When the output voltage Vb of the rechargeable battery device 4 is the charge control microcomputer 2 operable voltage Vm, the charging current Ib is Ib = (Vo-Vm) / R, and this current is deep as the preliminary charging current Ib. The current of a light load that can charge the rechargeable battery device 4 for discharge, that is, the standard charge rate (1 / 10C as the center, which is greater than the self-discharge rate).
/ 15C to 1 / 7C range), a charging rate of 1 / 30C to 1 / 20C, a capacity of 1200mA
For the rechargeable battery device 4 of h, the charging current is set to 40 mA to 60 mA. In this case, the heavy load occurs when the output voltage of the rechargeable battery device 4 is 0v due to deep discharge or a short circuit, and the maximum precharge current is Vo / R. The pre-charge current value is set so that this load is lighter than the quick charge load. For example, 1C to 2C
Assuming that the rapid charging current of the charging rate of 1,200mAh capacity
Rechargeable battery device 4 is 1200 mA to 2400 m
Vo and R are determined so that they are smaller than the charging current of A.

As described above, since the pre-charging circuit 7 is configured, only one resistor is required, and the size is small and the mounting space can be reduced. Also, an example in which the charge control microcomputer 2 is used for charge control is shown, but an electronic circuit may be used instead of the microcomputer. Further, the charge control microcomputer 2 reads the output voltage of the rechargeable battery device 4 through the A / D converter and compares it with a predetermined voltage.
Instead of using the D converter, a method of providing a comparison circuit for the output voltage of the rechargeable battery device 4 and a predetermined voltage and reading the output may be used.

Example 2. In this embodiment, as shown in FIG.
The pre-charging circuit 7 of the first embodiment is composed of a resistor and a semiconductor. In the figure, R1 and R2 are resistors and FETs
Reference numeral 1 is a field effect transistor, and the other parts are the same as those in FIG. In FIG. 4, resistors R1 and R2 of the pre-charging circuit 7 are voltage dividing resistors for applying a constant voltage to the gate of the field effect transistor FET1. The drain-source operates as a resistor and a pre-charge current can flow.

Field effect transistor FET1 at this time
The resistance Rds between the drain and the source is determined by the characteristics of the field effect transistor FET1 and the voltage Vgs applied between the gate and the source. As in the case of the first embodiment, the charging current is V0, the output voltage of the rechargeable battery device 4 is Vb, and the resistance Rds between the drain and the source is Rds. Current is (Vo-Vb)
/ Rds. That is, the resistor R of the first embodiment is replaced with Rds.

When the output voltage Vb of the rechargeable battery device 4 is the charge control microcomputer 2 operable voltage Vm, the current (Vo-Vm) / Rds is a light load current that can charge the deep discharge rechargeable battery device 4. That is, the standard charge rate is larger than the self-discharge rate (1 / 10C centered at 1 / 15C
~ 1 / 7C range) smaller charging rate, eg 1/30
It is set so that the current is determined by the charging rate of C to 1 / 20C. In this case, when the output voltage of the rechargeable battery device 4 is 0v due to a deep discharge or a short circuit, the maximum load is to flow the maximum Vo / Rds as the preliminary charging current, but this current value is the rapid charging. Use a value less than the current. Then, the gate-source voltage Vgs that becomes the on-resistance Rds is obtained from the characteristics of the field effect transistor FET1, and the values of the voltage dividing resistors R1 and R2 are determined from the voltage applied to the gate.

In the first embodiment, for example, the preliminary charging current is set to 50 m.
When the power supply voltage Vo is set to 15 V and the power supply voltage Vo is set to 15 V, the resistor R of the pre-charging circuit 7 needs to have a resistance of 2 to 3 W, so that the surface mounting type component cannot be used and the insertion type component is required. The field effect transistor of 2 to 3 W of this embodiment can be of a surface mounting type, and can be automatically assembled on a surface mounting line, which facilitates manufacturing. Further, the resistors R1 and R2 are voltage dividing resistors for determining the voltage applied to the gate of the field effect transistor FET1. Since the gate of the field effect transistor has high impedance, the resistors R1 and R2 are 1 /
It can be composed of a small surface mount resistor of about 10 W.

Example 3. In this embodiment, as shown in FIG.
The precharging circuit 7 of the first embodiment is composed of a constant current circuit. In FIG. 5, TR1 is a transistor, R3,
R4 is a resistor, D is a constant voltage diode, and others are the first embodiment.
The description is omitted because it is the same as FIG. Next, the operation will be described. When a current flows through the resistor R3 and the constant voltage diode D, a constant voltage Vz drops in the constant voltage diode D, and a current flows through the base of the transistor TR1. Then, the same voltage as that of the constant voltage diode D is applied to the base / emitter of TR1 and the resistor R4 which are connected in parallel to the constant voltage diode D.

In addition, since the base-emitter voltage Vbe of the transistor is generally constant, a constant voltage is applied to the resistor R4. Therefore, from the relationship of (voltage applied to resistance) / resistance value being constant, the pre-charging current Ib is constant irrespective of the load as shown in the following equation. Ib = (Vz-Vbe) / R4 And, in this case as well, the preliminary charging current Ib is the same as in the first embodiment.
Is a charging rate larger than the self-discharge rate and smaller than the standard charging rate (range of 1 / 15C to 1 / 7C centering on 1 / 10C), for example, a charging rate of 1 / 30C to 1/20, and a capacity of 1200 m.
In the case of the Ah rechargeable battery device 4, the current is set to 40 mA to 60 mA.

As described above, the rechargeable battery device 4 can be charged with a constant current. In addition, comparing the maximum power loss of this embodiment with those of the first and second embodiments under the following conditions: (1) Output voltage of the external power supply device 5: V0 = 15v (2) Charging current: Ib = 50mA (3) Charging Operable voltage of control microcomputer 2: Vm = 6
v In the case of the present embodiment, the maximum power loss during precharging is 15v × 0.05A = 0.75W when the output of the rechargeable battery device 4 is 0v.

In the case of Example 1 and Example 2, the maximum charging current is 0.05A × 15v / (15v−6v) = 0.083A when the output of the rechargeable battery device 4 is 0v. The power loss is 15v × 0.083A = 1.25W Therefore, this embodiment can reduce the power loss by 60% as compared with the first and second embodiments. The charging current when the pre-charging circuit 7 of the first embodiment is composed of the resistor R is (Vo-Vb).
/ R advances charging and output voltage Vb of rechargeable battery device 4
However, the constant current charging of the present embodiment charges at a constant current, so that the charging current can be efficiently charged.

Example 4. In this embodiment, the same functions as those of the quick charge ON / OFF switch circuit 1, the precharge ON / OFF switch circuit 6 and the precharge circuit 7 of the second embodiment are combined with a small number of parts. It is a thing. FIG. 6 shows the rapid charging ON / OFF switch circuit 1, the preliminary charging ON / OFF switch circuit 6, and the preliminary charging circuit 7 of the second embodiment, and FIG. 7 shows the present embodiment. In FIG. 6, R1 and R2 are resistors and FETs
1, FET4, FET5 are field effect transistors, TR
4 and TR5 are transistors, and the number of parts is 7. Others are the same as in the first embodiment. Although the field effect transistors FET4 and FET5 are of P-channel type in this embodiment, they may be N-channel. In the case of the P-channel, the gate potential may be lower than the source potential so that a negative potential difference is generated in the gate-source voltage (Vgs). In the case of N-channel, the gate
The gate potential may be set higher than the source and drain potentials so that a positive potential difference is generated in the source-to-source voltage (Vgs).

Next, when the charge control microcomputer 2 outputs a quick charge ON command, the operation of the base of the transistor TR4 is started.
A current flows between the emitters and the transistor TR4 is turned on. Then, the potential of the gate of the field effect transistor FET4 becomes approximately 0 v (saturation voltage of TR4), a negative potential difference is generated between the gate and the source, the drain and the source of the FET4 become conductive, and the external power supply device 5 charges the battery. A quick charge current flows through the battery device 4. Next, when the charge control microcomputer 2 outputs a command to turn off the quick charge, no current flows between the base and emitter of the transistor TR4, and the transistor TR4 is turned off.

Then, the field effect transistor FET4 is turned off, the source-drain is cut off, and the rapid charging current does not flow. Then, when the charge control microcomputer 2 outputs a command for turning on the preliminary charge, the transistor TR5 is turned on. The field effect transistor FET5 is the FE
According to the same principle as T4, the source and the drain are electrically connected, and the preliminary charging current flows from the external power supply device 5 to the rechargeable battery device 4 through the preliminary charging circuit 7. In addition, the charge control microcomputer 2
When the transistor outputs the command to turn off the precharge, the transistor TR
5 turns off. And field effect transistor FET
5 is turned off, the source-drain is cut off, and the charging current does not flow.

On the other hand, in FIG. 7, R1 and R2 are resistors. FET1 is a field effect transistor that functions to flow a precharge or quick charge current, FET2 is a field effect transistor that controls on / off of quick charge, and FET3 is a field effect transistor that controls on / off of precharge. Others are the same as in the first embodiment. The number of parts is five. The field effect transistor FET1 is of P-channel type, and the field effect transistors FET2 and FET3 are of N-channel type. It is also possible to use N-channels for FET1, but in that case they are driven to a potential higher than that applied to the drain or source.

Next, when the charge control microcomputer 2 outputs a quick charge ON command, the field effect transistor FET2 is operated.
Is turned on, and the field effect transistor FET1 conducts between the source and drain by the same principle as the FET4,
A rapid charging current flows from the external power supply device 5 to the rechargeable battery device 4. Next, the charge control microcomputer 2 sets the quick charge OF.
When the F command is output, the field effect transistor FET2 is turned off, but the operation of the field effect transistor FET1 is determined by the precharge ON / OFF command from the charge control microcomputer 2.

That is, the charge control microcomputer 2 causes the preliminary charge O
When the N command is output, the field effect transistor FET3 is turned on, and the resistors R1 and R2 and the field effect transistor FET1 have the same configuration as the precharge circuit 7 of FIG.
Field effect transistor FET as described in the second embodiment
1 works as a resistance. A preliminary charging current flows from the external power supply device 5 to the rechargeable battery device 4 via this circuit.
When the charge control microcomputer 2 outputs a precharge OFF command, the field effect transistor FET3 is turned off,
Then, the field effect transistor FET1 is turned off, the source-drain is cut off, and the precharge current does not flow.

With the above configuration, in the circuit shown in FIG. 6 of the second embodiment, the rapid charging current is made to flow by the field effect transistor FET4, and the preliminary charging current is made to the FET1 and FE.
In the circuit of FIG. 7 according to the present embodiment, the field effect transistor FET1 performs the above-described function by supplying the rapid charging current or the preliminary charging current, whereas the number of components can be reduced. In addition, the field effect transistor F of FIG.
ET2 and FET3 need only flow a weak current for applying a voltage to the high-impedance gate of the field effect transistor FET1, and mini-mold small surface-mounted components can be used.

Example 5. In the present embodiment, if the charging voltage of the rechargeable battery device 4 does not reach the operable voltage of the charging control microcomputer 2 even if the preliminary charging is performed for a certain period of time, the preliminary charging is stopped as a charging abnormality. The configuration diagram of this embodiment is the same as that of FIG. 1 of the first embodiment, and the description of the configuration is omitted. FIG. 8 shows a flowchart of the charging control executed by the charging control microcomputer 2. FIG. 8 is obtained by adding step 10 to FIG. 2 of the first embodiment.

In the figure, the charging control microcomputer 2 starts charging in step 1, and in step 2, the rapid charging ON / OFF switch circuit 1 is turned off so that the charging control microcomputer 2 performs preliminary charging, and the preliminary charging ON / OFF switch circuit is turned on. 6 is turned on. Then, in step 3, the charge control microcomputer 2 reads the output voltage of the rechargeable battery device 4 via the A / D converter 10 and reads the output voltage of the rechargeable battery device 4, and the operable voltage of the charge control microcomputer 2, for example, 6 V or more. If it is less than 6v, step 1
0, the rechargeable battery device 4 for a specified time, that is, for normal operation
Then, it is determined whether or not the time that should reach the operable voltage of the charge control microcomputer 2 has elapsed after starting the preliminary charging.

When the stipulated time has elapsed, the process proceeds to step 9 and the charging is judged to be abnormal and the charging is stopped. If the specified time has not elapsed, the procedure returns to step 2 to continue the preliminary charging. 6v
If so, the process proceeds to step 4, where the charge control microcomputer 2 turns off the preliminary charge ON / OFF switch circuit 6 and controls the rapid charge ON / OFF switch circuit 1 to ON until the output voltage of the rechargeable battery device 4 stabilizes. For a period of time, for example, rapid charging for 3 minutes. The subsequent steps are the same as those in FIG.

Here, for a specified time, for example, a nickel-cadmium battery whose output voltage has dropped due to deep discharge is generally activated by precharging within 1 minute and the output voltage is set to an operable voltage of the charge control microcomputer 2. Since it can be pulled up, the specified time may be set to 1 minute. Therefore, the parts of the pre-charging circuit do not have to have the performance to withstand the heat generation determined by the rating, and the parts that can withstand the heat generation corresponding to one minute can be well miniaturized.

Similar to the first, second and third embodiments, the precharging circuit 7 of the present embodiment can be configured as shown in FIGS. 3, 4 and 5. In addition, the quick charge ON / O of this embodiment
The FF switch circuit 1, the pre-charging ON / OFF switch circuit 6, and the pre-charging circuit 7 may be configured as shown in FIG.

Example 6. In the present embodiment, before rapidly charging the rechargeable battery device 4, the inactive rechargeable battery device 4 is activated in the pre-charging to distinguish whether the rechargeable battery device 4 includes a short-circuit cell. is there. Since it is not possible to distinguish whether the rechargeable battery device 4 includes a short-circuit cell or not in the preliminary charging rate of the first embodiment as will be described later, in this embodiment, the charging current is increased and the deep discharge cell 12 is quickly raised in voltage. It is intended to distinguish from the short-circuited cell 12. In the present embodiment, since a larger amount of charging current is supplied in the precharging than in the first embodiment, the components used in the precharging circuit are large, but the presence or absence of a short circuit is to be detected quickly. The configuration of this embodiment is the same as that of the first embodiment shown in FIG. The pre-charging current of this embodiment is a standard charging rate higher than that of the first embodiment, that is, a current determined by a charging rate of 1 / 15C to 1 / 7C, and a charging current of 80mA to 170mA for a rechargeable battery device 4 having a capacity of 1200mAh. Pre-charge. FIG. 9 shows a flowchart of charging control executed by the charging control microcomputer 2.

In the figure, the charging control microcomputer 2 starts charging in step 1, and in step 2, the rapid charging ON / OFF switch circuit 1 is turned off so that the charging control microcomputer 2 performs preliminary charging, and the preliminary charging ON / OFF switch circuit is turned on. 6 is turned on. Then, the voltage of the deep discharge rechargeable battery device 4 is restored, and the rechargeable battery device 4 is restored.
Pre-charging is performed for 3 minutes, for example, until the output voltage becomes stable.

Next, in step 3, the charge control microcomputer 2 reads the output voltage of the rechargeable battery device 4 via the A / D converter 10 and determines whether or not there is a short-circuited cell 12. The determination method is based on whether the charging voltage of the rechargeable battery device 4 is a reference voltage, for example, 8 V or higher. If it is less than the reference voltage 8v, the process proceeds to step 7 and the charging is judged to be abnormal and the charging is stopped. If the reference voltage is 8v or higher, step 4
Then, the charging control microcomputer 2 turns off the pre-charging ON / OFF switch circuit 6 and controls the rapid charging ON / OFF switch circuit 1 to turn on the rapid charging. Then, in step 5, it is determined whether the rechargeable battery device 4 is fully charged. If the battery is fully charged, it is determined that the charging is normal and the process proceeds to step 6 to stop the charging. If not fully charged, the process returns to step 4 to continue rapid charging.

Regarding the charging current, generally, at the charging rates of 1 / 30C to 1 / 20C of the first embodiment, the charging control microcomputer 2 cannot identify the presence or absence of the short-circuit cell 12 by the output voltage of the rechargeable battery device 4. For example, if the rechargeable battery device 4 is charged to 6v, the six normal cells 12 may be charged to 1.0v, respectively, reaching 1.0v × 6 = 6v, or one short circuit. Cell 12 and 5 normal cells 1
Normal cell 12 including 2 is charged to 1.2v and 0v x
Since 1 + 1.2v × 5 = 6v may be reached,
Cannot identify the presence or absence of a short circuit.

Therefore, the charging rate is set to the standard charging rate, for example, 1
When it is raised to the range of 1 / 15C to 1 / 7C around / 10C, the charging voltage per cell generally reaches 1.35v but does not exceed 1.5v within 3 minutes. When the charging voltage of the rechargeable battery device 4 includes 6 normal cells 12, the charging voltage reaches 1.33v × 6 = 8v when the battery is charged to 1.33v, whereas the short circuit cell 1
Normal cell 12 if 5 and 5 normal cells 12 are included
Even if the battery is charged to 1.5v, 0v x 1 + 1.5v x 5 =
Since 7.5v does not reach 8v, the charging control microcomputer 2 can determine whether or not one or more short-circuit cells 12 are included by the output voltage of the rechargeable battery device 4 if the reference voltage for short-circuit determination is selected to be 8v.

As described above, during preliminary charging at the standard charging rate, the deep-discharge rechargeable battery device 4 can be activated, and the presence or absence of a short circuit in the cell 12 built in the rechargeable battery device 4 can be detected quickly. The charging work can be shortened. Since the operable voltage of the charging control microcomputer 2 is 6v, which is lower than 8v of the short circuit determination of the present embodiment, the check of the operable voltage is omitted. However, if the operable voltage is 8v or more, the output voltage of the rechargeable battery device 4 is After confirming that the voltage has reached that level, switch to quick charge. Similar to the first, second, and third embodiments, the precharge circuit 7 of the present embodiment can be configured as shown in FIGS. 3, 4, and 5. In addition, the quick charge ON / OFF switch circuit 1 of this embodiment, the preliminary charge ON / OFF
The OFF switch circuit 6 and the pre-charging circuit 7 can be configured as shown in FIG.

Example 7. This embodiment is a charge control microcomputer 2
By taking the power source of the above from the rechargeable battery device 4, it is possible to prevent the rechargeable battery device 4 including the deeply discharged or short-circuited cells 12 from being charged as in the conventional example by repeating intermittent recovery from inoperability. To do. That is, the output of the rechargeable battery device 4 is the charge control microcomputer 2
If it can be driven, it is charged. If it cannot be driven, it is not charged.
The structure of this embodiment is shown in FIG. FIG. 10 shows the conventional example shown in FIG.
The constant voltage power supply device 3 of No. 1 is different from the external power supply device 5 in that it is connected to the rechargeable battery device 4. Since the others are the same, the description is omitted.

Next, the operation will be described. When the rechargeable battery device 4 is attached, the charge control microcomputer 2 operates,
If the rechargeable battery device 4 has a capacity that allows the charge control microcomputer 2 to operate normally, charging is performed by turning off the power switch (not shown) of the electronic device body 13 while the external power supply device 5 is powered on. The control microcomputer 2 turns on the quick charge ON / OFF switch circuit 1 to rapidly charge the rechargeable battery device 4. The subsequent operation is the same as that of the conventional example shown in FIG.

Next, if the output voltage of the rechargeable battery device 4 does not reach the operable voltage of the charging control microcomputer 2, the charging control microcomputer 2 cannot control the charging, and the rapid charging is turned on / off.
The switch circuit 1 is never turned on. As described above, charge control cannot be performed unless the rechargeable battery device 4 has a capacity for operating the charge control microcomputer 2 normally. Therefore, the rechargeable battery device 4 in the deep discharge state or the short-circuited state as in the conventional example is used. When the quick charge is performed, the charge control microcomputer 2 cannot operate and is repeatedly recovered, and the quick charge is not intermittently performed.

[0071]

According to the first aspect of the present invention, the charging control means performs quick charging when the charging voltage of the rechargeable battery device reaches a voltage at which it can be rapidly charged. Because of the battery device 4, the charge control microcomputer 2 does not become inoperable. Further, since the charging control means charges the rechargeable battery device with a weak current having a light load before performing the rapid charging, the deep-discharge rechargeable battery device is charged with this weak current to raise it to a voltage capable of rapid charging. After that, you can charge quickly. Furthermore, since the pre-charging is performed with a weak current, a small component with low power consumption can be used in the pre-charging circuit.

According to the second aspect of the invention, since the pre-charging is completed within a predetermined short time, the parts of the pre-charging circuit do not need to have the performance to withstand the heat generation determined by the rating, and the parts can withstand the heat generation within the specified time. Can be miniaturized well.

In the third aspect of the invention, since the precharge is performed at the standard charge rate, the charge control microcomputer 2 does not become inoperable due to the rechargeable battery device 4 which is deeply discharged or short-circuited as in the conventional example. Further, the presence or absence of a short circuit in the cell 12 built in the rechargeable battery device 4 can be quickly detected, and the charging work can be shortened.

In a fourth aspect of the invention, the precharge circuit 7 is connected to the resistor 1
Since it is composed of two parts, the size can be reduced and the mounting space can be reduced.

In the fifth aspect of the present invention, since the surface-mounting type field effect transistor can be used, automatic assembly in the surface-mounting line becomes possible and the manufacturing becomes easy. Further, the circuit for applying a constant voltage to the gate of the field effect transistor may be a small-sized surface mount type component as long as it allows a weak current to flow.

In the sixth aspect of the invention, even if the rechargeable battery device is short-circuited, only a constant current flows, so there is little power loss, and charging is performed at a constant current, so efficient charging is possible.

According to the seventh aspect of the invention, one field-effect transistor is used so that the precharge or quick charge current can flow. Therefore, a small surface mount component can be used and the number of components can be reduced. The gate circuit that controls the field effect transistor is
It is possible to use small and surface mounting type parts if only a weak current is applied.

In the eighth aspect of the invention, since the rechargeable battery device supplies power to the charging control means, the charging control means cannot operate unless the charging capacity is sufficient for normal operation. When the rechargeable battery device 4 in the state of being short-circuited is rapidly charged, the charge control microcomputer 2
Does not operate, recovers repeatedly and does not intermittently perform rapid charging, and operation is stable.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram according to a first embodiment of the present invention.

FIG. 2 is a charging process chart according to the first embodiment of the present invention.

FIG. 3 is a diagram in which a precharge circuit according to the first embodiment of the present invention is configured by resistors.

FIG. 4 is a diagram in which a precharge circuit according to a second embodiment of the present invention is configured with a semiconductor and a resistor.

FIG. 5 is a diagram in which a pre-charging circuit according to a third embodiment of the present invention is configured by a constant current circuit.

FIG. 6 is a diagram showing a circuit for switching between preliminary charging and quick charging according to a fourth embodiment of the present invention.

FIG. 7 is a diagram in which the above-described circuit of Embodiment 4 of the present invention is configured with a small number of parts.

FIG. 8 is a charging process chart according to a fifth embodiment of the present invention.

FIG. 9 is a charging process chart according to Example 6 of the present invention.

FIG. 10 is a circuit configuration diagram of a seventh embodiment of the present invention.

FIG. 11 is a conventional circuit configuration diagram.

FIG. 12 is a conventional charging process chart.

[Explanation of symbols]

 1. Quick charge ON / OFF switch circuit 2. Charge control microcomputer 3. Constant voltage power supply 4. Rechargeable battery device 5. External power supply 6. Pre-charge ON / OFF switch circuit 7. Pre-charging circuit 10. A / D converter 12. Cell 13. Electronic device body

Claims (8)

[Claims] 1. A charging device having the following components. 1. 1. Pre-charging means for charging the rechargeable battery device with a current larger than the self-discharge current and smaller than the standard charge current according to the capacity of the rechargeable battery device; 2. quick charging means for charging the rechargeable battery device with a current larger than a standard charging current according to the capacity of the rechargeable battery device; 3. Comparison means for comparing a predetermined reference voltage determined in advance with the charging voltage of the rechargeable battery device; Charging by the preliminary charging means, comparing the reference voltage with the charging voltage of the rechargeable battery device by the comparing means, if this charging voltage is higher than the reference voltage,
Charging control means for controlling to perform rapid charging by the rapid charging means. 2. The charging control means charges by the preliminary charging means, and after a predetermined time, the comparing means compares the reference voltage with the charging voltage of the rechargeable battery device, and the charging voltage is the reference voltage. The charging device according to claim 1, wherein the charging device is controlled so as to stop charging if it is lower. 3. A charging device having the following components. 1. 1. Pre-charging means for charging with a standard charging current according to the capacity of the rechargeable battery device; 2. quick charging means for charging the rechargeable battery device with a current larger than a standard charging current according to the capacity of the rechargeable battery device; After charging for a predetermined time, a voltage that can be reached by a normal rechargeable battery device and cannot be reached by a rechargeable battery device including a short-circuited cell is used as a reference voltage, and this reference voltage is compared with the charging voltage of the rechargeable battery device. 3. comparison means, The pre-charging means charges the battery, and after a predetermined time, the comparing means compares the reference voltage with the charging voltage of the rechargeable battery device. If the charging voltage is lower than the reference voltage, the charging is stopped. Charging control means for controlling the charging by the charging means. 4. The charging device according to claim 1, wherein the pre-charging means is composed of a resistance element. 5. The charging device according to claim 1, wherein the pre-charging means comprises a field effect transistor having a gate to which a constant voltage is applied. 6. The method according to claim 1, wherein the pre-charging means is composed of a constant current circuit.
The charging device described. 7. The pre-charging means and the charge control means control a field-effect transistor that causes a pre-charging current or a rapid charging current to flow, and a first switching that controls the field-effect transistor to cause the rapid charging current to flow. An element and a second switching element for controlling the field effect transistor so as to allow the pre-charging current to flow, and the second switching element is provided.
The charging device described. 8. A charging device having the following components. 1. 1. Rapid charging means for charging the rechargeable battery device with a current larger than the standard charging current according to the capacity of the rechargeable battery device. 2. Charge control means for controlling to charge by the quick charge means, Power supply means for supplying power from the rechargeable battery device to the charge control means.