JPH05152005A - Battery charging device - Google Patents

Abstract

PURPOSE:To exactly judge abnormality of a secondary battery or a charging device itself by measuring abnormality according to a detection result of an interterminal voltage detection means of a secondary battery to be charged and a charging current detection means in order to give warning. CONSTITUTION:In case an information signal to be transmitted from a current detection circuit 4 and a charging voltage detection circuit 8 is showing an abnormal level, a microcomputor 1 for control makes a display circuit 9 to perform display showing a trouble of a charging device so as to store the information corresponding to the contents followed by stopping charging operation. Further, the contents of an information signal transmitted from a terminal voltage detection circuit 7 are watched and in case a terminal voltage level is abnormally changed, the display circuit 9 is made to display showing a defect of a secondary battery 6 to be charged to store the information corresponding to the displayed contents followed by stopping charging operation. Accordingly, generated abnormality on the secondary battery or the charging device itself is exactly judged so as to inform a user thereof for improving operability and safety.

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 a secondary battery.

[0002]

2. Description of the Related Art In a conventional charging device, a terminal voltage of a secondary battery to be charged during a charging operation is measured, and the charging operation is controlled according to a variation state of the terminal voltage.

That is, when the voltage between the terminals of the secondary battery draws a predetermined charging voltage curve, the charging operation is stopped and an indication that the charging is completed is displayed, and the voltage between the terminals of the secondary battery is charged. If the charging voltage curve showing the abnormal state of operation is drawn, the charging operation was stopped.

For example, in the case of a general NiCd secondary battery, the charging terminal voltage curve as shown in FIG. 2 is shown, and the charging current is being supplied as in the period indicated by Δt1 in the drawing. When it is confirmed that the charging terminal voltage of + is increased by + ΔV, the charging operation is continued as it is, and the charging terminal voltage is decreased by -ΔV as in the period indicated by Δt2 in the figure. When this was confirmed, it was determined that the secondary battery being charged was fully charged, the supply of charging current was stopped, and the charging operation was completed.

When the secondary battery and the charging device are normal and the charging operation is normal, the charging terminal voltage of the secondary battery draws a curve as shown in B of FIG. When an abnormality occurs in the secondary battery or the charging device and the normal charging operation cannot be performed, for example, a curve as shown in A of FIG. 3 is drawn. When it is detected that the terminal voltage of the secondary battery draws a curve as shown in FIG. 3A during charging by the microcomputer for controlling the secondary battery which monitors the state of the terminal voltage. The microcomputer for controlling the secondary battery determines that an abnormality has occurred in the charging operation, stops supplying the charging current to the secondary battery, and suspends the charging operation.

[0006]

However, in the conventional charging device as described above, the voltage between the terminals of the secondary battery is monitored and the charging operation is controlled. When it was not possible to perform proper charging, it was not possible to determine whether the charging device had an abnormality or the secondary battery was defective.

The present invention, with a simple and low-cost configuration, is capable of accurately deciding that an abnormality has occurred in the secondary battery or the charging device itself and surely notifying the user of operability and safety. The purpose is to provide a charging device with good performance.

[0008]

A charging device of the present invention is a device for charging a secondary battery, comprising terminal voltage detecting means for detecting a terminal voltage of the secondary battery for charging, and the secondary battery. A charging current detection unit that detects a charging current supplied to a battery, and a charging operation state for the secondary battery is monitored according to the detection results of the terminal voltage detection unit and the charging current detection unit. And a warning unit that warns the user according to the determination result of the determination unit.

[0009]

According to the above-mentioned structure, it is possible to accurately judge that there is an abnormality in the secondary battery or the charging device itself and to notify the user with certainty by a simple and low-cost structure. It is possible to improve operability and safety.

[0010]

EXAMPLES The present invention will be described below with reference to examples of the present invention.

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

In FIG. 1, reference numeral 1 is a control microcomputer (hereinafter, abbreviated as control microcomputer) which controls each circuit for performing charging operation of a secondary battery and detection operation of a charging state, and 2 is the control microcomputer 1 A charge control circuit for starting / stopping the charging operation under the control of 3 is a switch for transmitting / discharging the charging current, 4 is a current detection for converting the charging current flowing in the secondary battery into a voltage and transmitting it to the control microcomputer 1. circuit,
Reference numeral 5 is a secondary battery connection terminal for connecting a secondary battery, 6 is a secondary battery to be charged, 7 is a terminal voltage detection circuit for detecting the terminal voltage at the secondary battery connection terminal 5, and 8 is a charge control circuit 2
A charging voltage detection circuit for detecting the voltage at the output terminal of the control circuit 9 and a display circuit 9 for displaying the control operation of the control microcomputer 1.

Further, FIG. 4 is a view showing an operation flowchart at the time of charging operation in the charging device of the present embodiment shown in FIG.

The charging operation of the charging device of this embodiment will be described below with reference to FIGS. 1 and 4.

In FIG. 1, a rechargeable secondary battery 6 is mounted on a charging device, a contact point of the rechargeable secondary battery 6 and a rechargeable battery connecting terminal 5 are connected, and an operating portion (not shown) is operated. As a result, when the control microcomputer 1 is instructed to start the charging operation, the control microcomputer 1 starts the operation of the charging timer provided therein and counts down the preset charging operation time. Start (see S1 in FIG. 4).

When the count value in the charging timer has not reached the preset charging operation time, the control microcomputer 1 instructs the charging control circuit 2 to start the charging operation, and the charging operation is started. The charging control circuit 2 which is instructed to start supplies the charging current to the secondary battery 6 to be charged through the current detection circuit 4 by turning on the switch 3 (see S2 and S3 in FIG. 4). ..

While the charging operation is being performed as described above, the current detection circuit 4 converts the amount of charging current supplied from the charging control circuit 2 into a voltage level and responds to the voltage level. When an information signal is transmitted to the control microcomputer 1 and the control microcomputer 1 transmits an information signal indicating an abnormal level, the display circuit 9 displays an indication that the charging device has failed, and After the information corresponding to the display contents on the display circuit 9 (that is, the information indicating that the charging device has a failure) is stored in the memory provided in the control microcomputer 1, the charging operation is stopped. (See S4, S5, S13, S15 in FIG. 4).

When the information signal transmitted from the current detection circuit 4 indicates a normal level, the charging voltage detection circuit 8 detects the voltage at the output terminal of the charging control circuit 2 and detects it. When an information signal corresponding to the voltage level is transmitted to the control microcomputer 1 and the information signal transmitted by the control microcomputer 1 indicates an abnormal level, the display circuit 9 indicates a failure of the charging device. After the display is performed and the information corresponding to the display content on the display circuit 9 is stored in the memory provided in the control microcomputer 1 (that is, the information indicating that a failure has occurred in the charging device) , The charging operation is stopped (S6 in FIG. 4,
(See S7, S13, S15).

As described above, in the control microcomputer 1,
When it is detected that no failure has occurred in the charging device based on the information signals transmitted from the current detection circuit 4 and the charging voltage detection circuit 8, the terminal voltage detection circuit 7 outputs the terminal voltage at the secondary battery connection terminal 5. Is detected and an information signal corresponding to the detected terminal voltage level is transmitted to the control microcomputer 1, and the control microcomputer 1 monitors the content of the information signal transmitted from the terminal voltage detection circuit 7, When the voltage level changes as shown in FIG. 3A, the display circuit 9 displays an indication that the secondary battery 6 to be charged is defective and is provided in the control microcomputer 1. After the information corresponding to the display content on the display circuit 9 (that is, the information indicating that the secondary battery 6 to be charged is defective) is stored in the memory, the charging operation is stopped (see FIG. 4).
S8, S9, S14, S15), and the information signal transmitted from the terminal voltage detection circuit 7 causes the terminal voltage level to change as shown in B of FIG. If it is determined to be normal, the operations shown in S2 to S10 of FIG. 4 are repeated, and the control microcomputer 1 continues to monitor the content of the information signal transmitted from the terminal voltage detection circuit 7. When it is detected that the terminal voltage level has decreased by −ΔV as in the period indicated by Δt2 in FIG. 4, it is determined that the secondary battery 6 to be charged is fully charged, and the display circuit 9 After the display indicating the completion of charging is displayed, the charging operation is stopped (S10 and S11 in FIG. 4).
reference).

Further, even after the preset charging operation time counted down by the charging timer of the control microcomputer 1 has elapsed, the terminal voltage level is set to the level shown in FIG.
If it is not detected that the voltage has decreased by -ΔV as in the period indicated by Δt2, the display circuit 9 displays an indication that the secondary battery 6 to be charged is defective and is provided in the control microcomputer 1. After the information corresponding to the display content on the display circuit 9 (that is, the information indicating that the secondary battery 6 to be charged is defective) is stored in the memory, the charging operation is stopped (S2 and S12 in FIG. 4). , S15).

By the way, as a display form in the display circuit 9 of FIG. 1, for example, an LED (Light) for power supply display is used.
Emitting Diode), LED for charging operation display, LED for charging device abnormality display, LED for secondary battery failure display are provided, and the power supply of the charging device is turned on by operating an operation unit (not shown). When turned on, the LED for displaying the power source is turned on, when the charging operation is normally performed, the LED for displaying the charging operation is turned on, and when the charging operation is performed, the charging device or When an abnormality occurs in the secondary battery, the LED for indicating the abnormality in the charging device or the LED for indicating the secondary battery failure is turned on (or blinks) according to the occurrence state to notify the user. Is configured.

When an abnormality occurs in the charging device or the secondary battery during the charging operation as described above, the LE for displaying the abnormality of the charging device is displayed according to the occurrence state.
It is also possible to turn on (or blink) the LED for displaying D or the secondary battery failure and turn off the LED for displaying the charging operation.

The display form of the display circuit 9 in FIG. 1 is not limited to the above-mentioned form, and a liquid crystal display element or the like may be used to display characters. Further, the warning by the display circuit 9 is based on the display. Instead, it may be configured to emit a warning sound when notifying the user of a defective secondary battery or abnormality in the charging device, that is, a defective secondary battery or abnormality in the charging device to the user. Any means may be used as long as it can inform.

Further, the display circuit 9 may be provided not in the main body of the charging device but in a battery pack having a built-in secondary battery in which the charging device is mounted. In this case, for the control shown in FIG. The display circuit provided in the battery pack may be configured to display in response to an instruction from the microcomputer 1.

By the way, in this embodiment, since the current detection circuit 4 is provided as shown in FIG. 1 in order to detect the abnormality of the charging device during the charging operation, the voltage drop in the current detection circuit 4 is caused. Depending on the component, the charging current may be lost and the charging efficiency for the secondary battery 6 to be charged may be deteriorated. Therefore, the terminal voltage of each circuit in which a voltage drop occurs in the charging device and the electrically equivalent impedance of each circuit are determined. Consider,
It may be configured to detect an abnormality of the charging device based on the charging current by relatively monitoring the state of the charging current.

As described above, in this embodiment, when the secondary battery is being charged, if the normal charging operation is not performed, an abnormality occurs in the secondary battery or the charging device itself. That the user is
It is possible to appropriately inform whether the secondary battery is defective or the charging device is broken, and it is possible to improve the operability and safety of the device.

Further, in this embodiment, S15 in FIG.
Since the information provided in the control microcomputer 1 is stored in the memory corresponding to the display contents on the display circuit 9, the charging device fails by checking the contents of the information stored in the memory. It is possible to easily determine whether or not the attached secondary battery is defective, which is very useful for service management in case of failure.

[0028]

As described above, according to the present invention, it is possible to accurately judge whether an abnormality has occurred in the secondary battery or the charging device itself with a simple and low-cost configuration, and to ensure the user. It is possible to provide a charging device with good operability and safety that can be known to the public.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a charging terminal voltage curve of a general NiCd secondary battery.

FIG. 3 is a diagram showing a charging terminal voltage curve of a nickel cadmium secondary battery when an abnormality has occurred in the nickel cadmium secondary battery or the charging device.

FIG. 4 is a diagram showing an operation flowchart during a charging operation in the charging device shown in FIG.

[Explanation of symbols]

 1 Control Microcomputer 2 Charge Control Circuit 3 Switch 4 Current Detection Circuit 5 Secondary Battery Connection Terminal 6 Secondary Battery to Be Charged 7 Terminal Voltage Detection Circuit 8 Charging Voltage Detection Circuit 9 Display Circuit

Claims (1)

[Claims] 1. A device for charging a secondary battery, comprising: a terminal voltage detecting means for detecting a voltage between terminals of the secondary battery for charging; and a charging current detection for detecting a charging current supplied to the secondary battery. Means for monitoring the charging operation state of the secondary battery according to the detection results of the terminal voltage detection means and the charging current detection means, and determines whether the secondary battery is defective or the device is abnormal according to the monitoring result. A charging device, comprising: a determination unit that performs a warning, and a warning unit that warns a user according to a determination result of the determination unit.