JPH0731062A - Charger - Google Patents

Abstract

PURPOSE:To accurately judge whether a battery is normal or abnormal due to self-discharge. CONSTITUTION:After a battery pack PA charged by a charging circuit 5 is permitted to stand for a predetermined time, it is discharged by the circuit 5. This discharging time is measured by a battery abnormal detecting and displaying unit 6, and compared with a preset reference time. An LED 9 which emits a red light is lit when the discharging time is the reference time or less. On the other hand, an LED 8 which emits a green light is lit when the time exceeds the reference time. Thus, abnormality due to self-discharge can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for charging batteries used in portable computers, various electric devices and the like.

[0002]

2. Description of the Related Art As a charger having a function of determining whether a battery is abnormal or normal, there is one having a structure disclosed in Japanese Patent Laid-Open No. 3-7025. The device disclosed in the publication includes a voltage detection circuit that detects a terminal voltage value of a battery (hereinafter referred to as a battery pack) during charging, and a temperature sensor and a temperature detection circuit that similarly detect the temperature of the battery pack. , A microprocessor and.
In such a charger, the voltage value detected by the voltage detection circuit and the temperature detected by the temperature detection circuit are input to the microprocessor for discrimination. Specifically, the reference voltage range is set in advance in the microprocessor,
It is determined by comparing whether the detected terminal voltage of the battery pack is within the reference voltage range. If it is outside the above range, it is determined to be abnormal. On the other hand, when the temperature of the battery pack becomes abnormally high, the charging operation is stopped and the abnormality is displayed. In this way, the good or bad battery pack is determined.

[0003]

By the way, even when the detection circuit provided in the charger can determine that the specific battery pack is normal, when the battery pack is charged just before use, it is almost as planned. Although it can be continuously used for only the time, there is a phenomenon that when the battery is left for several days after charging, it is remarkably shortened. That is, it is impossible to detect a minute self-discharge phenomenon occurring inside the battery pack by a method of determining normality or abnormality based on a terminal voltage or a temperature change of the battery pack being charged as in the charger described above. Therefore, there is a drawback that an abnormal battery pack due to self-discharge as described above cannot be found. Therefore, when using, for example, a portable computer that uses only the battery pack as the only power source, for example, the power is unexpectedly turned off during the input operation, and the data being input or the data read in the main memory or the like is used. The problem that there is a risk that programs, programs, etc. may be lost, and that this requires frequent interruptions of work remains unsolved.

Therefore, an object of the present invention is to provide a charging device which can accurately determine whether the battery is normal or abnormal due to self-discharge.

[0005]

To achieve the above object, a charging device according to claim 1 is a discharging device for discharging a battery, which has been charged by the charging circuit, with a constant current after a lapse of a predetermined time. Measuring means for measuring the discharge time,
A discriminating means for discriminating normality or abnormality by comparing the measured discharge time with a preset reference time and a display means for displaying normality or abnormality of the battery based on the discrimination result are provided.

To achieve the same object, a charging device according to a second aspect is the charging device according to the first aspect, further comprising: a first timer circuit for setting a charging time from the start of charging to the completion of charging; A second timer circuit for setting the time from the completion of charging to the start of discharging by the discharging means is provided.

Further, in the charging device according to the third aspect, the recharging operation is performed by the charging circuit after the completion of the discharge by the discharging means when the judgment result by the judging means is normal.

[0008]

In the charging device described in claim 1, the battery, which has been completely charged by the charging circuit, is discharged at a constant current by the discharging means after a lapse of a predetermined time. The discharging time is measured by the measuring means and compared with the preset reference time by the judging means to judge normality or abnormality. The display means displays normal or abnormal according to the discrimination result of the discrimination means. In the charging device according to the second aspect, the battery is charged for the time set by the first timer circuit, and after the time set by the second timer circuit has elapsed, the battery is discharged at a constant current by the discharging means. .
The discharging time is measured by the measuring means and compared with the preset reference time by the judging means to judge normality or abnormality. The display means displays normal or abnormal according to the comparison result from the comparison means. Further, in the charging device described in claim 3, when the battery is normal in the charging device described in claim 1 or 2, the charging operation is performed again after the discharging by the discharging means is completed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an electrical configuration as one embodiment,
FIG. 2 is a timing chart showing an operating state of the charging device shown in FIG. 1, and FIG. 3 is a characteristic diagram showing battery pack voltage and battery cell temperature characteristics by constant current charging. Note that FIG.
In, the vertical axis represents the charging current, the battery cell temperature, and the battery pack voltage, and the horizontal axis represents the charging time.

The charging device shown in FIG. 1 includes a charging circuit 2 connected to an AC power source 1 via a switch SW, and a discharging circuit 5 connected to the charging circuit 2 via a relay contact R.
A battery abnormality detection / display unit 6 and first and second timer circuits 3 and 4 are provided. Further, PA in the drawing is a battery pack connected through a connection connector (not shown), and a nickel cadmium battery with a capacity of about 1000 mAh is assumed in this embodiment. The charging circuit 2 has a function of rapidly charging the battery pack PA with a constant current of 1 C (1000 mA in this embodiment) as shown by A in FIG. 3 in about one hour. When charging the battery pack PA made of a nickel-cadmium battery as shown in this embodiment, a voltage drop (-ΔV) occurs in the terminal voltage D at the end of charging of the battery pack PA as shown in FIG. Therefore, in the present embodiment, a detection circuit (not shown) for detecting a voltage drop (-ΔV) is provided in the charging circuit 2, and 0.02C to 0.C is detected after the voltage drop (-ΔV) is detected by the detection circuit. 0
A trickle current B having a relatively small current value of about 5 C (200 to 500 mA in this embodiment) is output, and the trickle current B is used for supplementary charging for about 1 hour. In the figure, E indicates the battery cell temperature.

The discharging circuit 5 has a function of discharging the battery pack PA charged by the charging circuit 2 with the constant current 1C described above. First timer circuit 3
Is activated by a charging start signal output from the charging circuit 2, and after the preset time (two hours in this embodiment) has elapsed, the relay contact R
Is turned off (open). On the other hand, the second timer circuit 4 is activated by a signal output when the time set by the first timer circuit 2 has elapsed, and discharges after the elapse of a preset time (48 hours in this embodiment). The discharge current output from the circuit 2 is used to detect battery abnormality.
The display section 6 is made to output.

The battery abnormality detection / display section 6 is connected to the battery abnormality detection / display circuit 7 and the DC resistance V through the protection resistor T.
It has two LEDs 8 and 9 to which cc is connected.
The battery abnormality detection / display circuit 7 measures the discharge time of the discharge current output from the discharge circuit 2 and compares the measured discharge time with a preset reference time (40 minutes in this embodiment). By this comparison, the LED 8 is turned on when the discharge time exceeds the reference time, and the LED 9 is turned on when the discharge time is shorter than the reference time. The discharge time of the discharge current is the time until the final voltage value of the discharge current becomes equal to or less than the predetermined voltage value in this embodiment. The LEDs 8 and 9 are one of the LEDs.
It is possible to intuitively determine normality or abnormality by using a device in which 8 emits blue light and the other LED 9 emits red light.

The operation state of the charging device having the above configuration will be described with reference to FIG. It should be noted that, here, the description will focus on the case where the normality or abnormality of the battery pack is determined. First, before starting the charging operation, the switch SW is off (open) and the relay contact R is on (closed). When the battery pack PA is connected in this state and the switch SW is turned on (closed) at the timing shown in FIG. 2A, the charging operation by the charging circuit 2 is started from this point. At the same time when the charging is started, a charging start signal is output from the charging circuit 2 and the first timer circuit 3
Works. This charging operation is the rapid charging A of the constant current 1C described above for the first hour, and 0.02 for the second hour.
The auxiliary charging is performed by the trickle current B of about to 0.05C. The both charging operations are completed by disconnecting the connection between the charging circuit 2 and the battery pack PA at the timing (b) when the relay contact R is turned off (open) by the first timer circuit 3. Further, the second timer circuit 4 is activated at the timing (b) when this charging operation is completed.

The discharge current from the battery pack PA is output to the battery abnormality detection / display circuit 7 via the discharge circuit 5 at the timing (c) when 48 hours set by the second timer circuit 4 has elapsed. To be done. The battery abnormality detection / display circuit 7 measures the discharge time of the input discharge current and compares the discharge time with the reference time. Then, when it is determined that the discharge time is equal to or shorter than the reference time, the LED 9 that emits red light that indicates an abnormality is turned on.
On the other hand, when the discharge time of the battery pack PA exceeds the reference time, the LED emits blue light indicating that the battery pack is normal.
Lighting control of No. 8 is performed. Also, at the timing (d) at which the LED 8 is turned on, the first and second timer circuits 3 and 4 are reset and the relay contact R is closed again to perform quick charge A for 1 hour, and then trickle current B for 1 hour. Perform supplementary charging by. Then, the battery pack P for which supplementary charging has been completed
If A is removed from the connection connector (not shown) and loaded into a portable computer or the like, it can be used immediately. When the battery pack is not judged to be normal or abnormal, the first rapid charging A or the like can be sufficiently used. Therefore, in this case, the battery pack PA may be detached from the connection connector (not shown) and used after the first rapid charge A or the like.

As shown in this embodiment, when judging whether the battery pack is normal or abnormal, the battery pack PA is left for a certain period of time after a predetermined charging operation, and then intentionally applied with a constant current. The battery pack PA is discharged and the discharge duration time of the battery pack PA is measured. This makes it possible to detect an abnormality based on self-discharge that could not be found in the past. Therefore, for example, when using a portable computer or the like that is driven only by the battery pack PA, it is possible to prevent accidents such as sudden power off. Furthermore, the battery pack PA determined to be normal in this embodiment can be continuously used for the expected predetermined time. Therefore, replacement of the battery pack during work can be suppressed as much as possible,
As a result, work efficiency can be improved. In addition,
The present invention is not limited to the scope shown or described above, and various modifications can be made within the scope of the gist thereof. For example, in each of the above embodiments, an example in which the set time of the timer circuit 4 is set to 48 hours has been described.
This set time may be increased or decreased according to the occurrence state of self-discharge. Even in this case, it is possible to obtain substantially the same effect as that of the above embodiment.

Further, in the above embodiment, an example in which the abnormality or the normality is judged based on the discharge time of the battery pack has been described, but the terminal voltage and temperature of the battery pack are also measured together with the measurement of this discharge time. The determination of abnormality or normality may be made based on each measurement result.

[0017]

According to the invention described in claim 1 or 2, it is possible to accurately determine whether the battery is normal or abnormal due to self-discharge after completion of charging. As a result, it is possible to suppress the replacement of the battery during the work as much as possible, thereby improving the work efficiency. Further, it is possible to perform a normal or abnormal inspection simply by leaving the battery as it is after the charging is completed. Further, according to the invention described in claim 3, in addition to the effect obtained in claim 1 or 2, when the battery is normal, the charging operation is performed again after the end of discharging, so that the battery can be immediately charged in a fully charged state. Will be able to use.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a charging device as an embodiment of the present invention.

FIG. 2 is a timing chart showing an operation state of the charging device shown in FIG.

FIG. 3 is a characteristic diagram showing battery pack voltage and battery cell temperature characteristics due to constant current charging.

[Explanation of symbols]

 1 Power Supply 2 Charging Circuit 3 First Timer Circuit 4 Second Timer Circuit 5 Battery Pack 6 Battery Abnormality Detection / Display 7 Battery Abnormality Detection / Display Circuit 8, 9 LED PA Battery Pack R Relay Contact T Protection Resistor

Claims (3)

[Claims] 1. A charging device having a charging circuit for charging a connected battery, and discharging means for discharging a battery, which has been charged by the charging circuit, with a constant current after a predetermined time has elapsed, and the discharging time is measured. A measuring means, a determining means for comparing the measured discharge time with a preset reference time to determine normality or abnormality, and a display means for displaying normality or abnormality of the battery based on the determination result are provided. Charging device characterized by. 2. A first timer circuit for setting a charging time from the start of charging to the completion of charging, and a second timer circuit for setting a time from the completion of charging to the start of discharging by the discharging means. 1. The charging device according to 1. 3. The charging device according to claim 1, wherein when the result of the determination by the determining unit is normal, the recharging operation is performed by the charging circuit after the discharging by the discharging unit is completed.