JPH04127075A - Battery residual capacity display device for rechargeable equipment - Google Patents

Abstract

PURPOSE:To enable accurate detection of a residual capacity of a battery by providing a charger and a battery pack with a charging end detection means, the battery pack with a full charge information holding means and an equipment body with a residual capacity computing circuit and a residual capacity display part. CONSTITUTION:When a battery pack 4 is mounted on an equipment body 1, a date of a residual capacity stored is set to a state of full charge by a full charge signal from a full charge information holding means 14 to be inputted into a residual capacity computing circuit 17 through an input terminal 18. Then, when a battery 5 is connected to a load 2 with a power source switch 3 to discharge, the circuit 17 subtracts a time product of a discharge value obtained sequentially from the residual capacity data set to the state of full charge to determine a residual capacity of the battery 5. A residual capacity display section 20 lights a plurality of display bodies 201 comprising LEDs by the number corresponding to the residual capacity to made a level display of the residual capacity.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention combines a rechargeable battery pack, a device body to which the battery pack is detachably attached, and a charger for charging the battery pack. The present invention relates to a remaining battery capacity display device for displaying the remaining capacity of a battery in a rechargeable device.

(Prior Art) Generally, a rechargeable device in which a battery pack can be attached to and detached from the device main body is configured by combining the device main body, a battery pack, and a charger.

A battery pack has a rechargeable battery such as a Ni-Cd battery built into a housing, and charging and discharging terminals connected to the battery are provided on the surface of the housing. It is removably attached to the device and charged using a charger. The main body of the device includes a load such as a motor, a battery pack is attached thereto, and current is supplied to the load from the positive and negative terminals of the battery pack. The charger includes a charging circuit that outputs a charging current, and supplies the charging current to the battery from the positive and negative terminals of the battery pack.

In such rechargeable devices, there has been a desire to display the remaining battery capacity in order to know when to charge the battery pack.

Furthermore, rechargeable devices in which a rechargeable battery is non-removably housed within the device, such as electric shavers, have been provided with a remaining battery capacity display device. this is,
The device is equipped with a remaining capacity detection circuit that detects the remaining capacity by determining the amount of charge and discharge that occurs in the battery when charging and discharging the battery built into the main body of the device. In this way, if the battery is non-removable, the remaining capacity detection circuit can constantly monitor the amount of charge put into the battery by charging and the amount of discharge released from the battery by discharging, so it is possible to accurately determine the remaining capacity of the battery. can be detected.

On the other hand, in the case of devices with detachable battery packs, the battery is discharged in the device itself, so the amount of discharge from the battery due to discharge can be detected by the device itself, but charging of the battery is done in the battery pack. Since the battery is removed from the device and used in a charger, it is impossible to monitor the amount of charge put into the battery from the device itself.

Therefore, when the battery pack is attached to the device, the battery voltage inside the battery pack is detected, the remaining capacity of the battery is determined from this battery voltage, and the amount of discharge from the battery due to discharge is determined from this remaining capacity. Therefore, devices equipped with a remaining capacity detection circuit that determines the remaining capacity of the battery have been provided.

[Problem B to be solved by the invention] However, in devices that detect the remaining capacity from the battery voltage, the correspondence between the battery voltage and the remaining capacity of the battery is not completely linear, so it is difficult to accurately determine the remaining capacity. There was a problem that it could not be detected. In particular, when the battery is a Ni--Cd battery, the battery voltage hardly corresponds to the remaining battery capacity, so when the above configuration is adopted, there is a problem in that the error becomes extremely large.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a battery remaining capacity that can accurately detect the remaining capacity of a battery in a rechargeable device in which a battery pack is detachably attached to the main body of the device. The object of the present invention is to provide a detection device.

[Means to solve the problem]

In order to solve this problem, the remaining battery capacity display device for a rechargeable device according to claim (1) includes a charging completion detection means for detecting that charging of the battery is completed and the battery is fully charged; The battery includes a full charge information holding means for holding information that the battery is in a fully charged state, a remaining capacity detecting means for determining the remaining capacity of the battery from the amount of discharge of the battery, and a remaining capacity display section for displaying the remaining capacity. , the charge completion detection means is provided in the charger or the battery pack, and the full charge information holding means is provided in the battery pack,
A remaining capacity detection means and a remaining capacity display section are provided in the main body of the device.

The remaining battery capacity display device for a rechargeable device according to claim (2) includes a remaining capacity detecting means for determining the remaining capacity of the battery from the amount of charge or discharge of the battery, and remaining capacity information that holds remaining capacity information of the battery. and a remaining capacity display section for displaying the remaining capacity, the remaining capacity detection means being provided on the charger and the device body, the remaining capacity information holding means being provided on the battery pack, and the remaining capacity display section being provided on the device body. It is set up.

In the battery remaining capacity display device for a rechargeable device according to claim (3), the remaining capacity information holding means in the battery remaining capacity display device according to claim (2) is formed of a nonvolatile memory.

[Effect]

In the battery remaining capacity display device for a rechargeable device according to claim (1), the charging completion detection means is provided in the charger or the battery pack, the full charge information holding means is provided in the flat battery, and the remaining capacity detection means is provided in the battery pack. With the feature 5 provided in the device body, when a fully charged battery pack is attached to the device body, information that the battery is fully charged is transferred from the battery pack's full charge information holding means to the remaining battery pack in the device body. The battery pack is attached to the main body of the device in order to detect the remaining capacity by subtracting the discharge amount due to battery discharge from the remaining capacity of the battery as the fully charged capacity. This allows you to accurately display the remaining capacity when discharging the battery.

In the remaining battery capacity display device for a rechargeable device according to claims (2) and (3), the remaining capacity detection means for determining the remaining capacity of the battery from the amount of charge or discharge of the battery is provided in the charger and the device body. By providing a remaining capacity information holding means for holding remaining capacity information in a flat battery, the remaining capacity information from the remaining capacity information holding means of a flat battery is passed to the remaining capacity detecting means of the charger during charging. Then, the remaining capacity detecting means adds the amount of charge due to battery charging from the remaining capacity information to detect the remaining capacity, and when a flat battery is attached to the device main body, the remaining capacity information holding means of the battery pack detects the remaining capacity. The remaining capacity information is passed to the remaining capacity detecting means of the main body of the device, and the remaining capacity detecting means subtracts the discharge amount due to battery discharge from the remaining capacity information to detect the remaining capacity. It can also accurately display the remaining battery capacity.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3 of the drawings.

Reference numeral 1 denotes a device main body which is an electric screwdriver equipped with a load 2 consisting of a motor, a power switch 3 connected to the load 2 is provided on the handle, and a remaining capacity display section 2 to be described later.
0 is provided on the side.

Reference numeral 4 denotes a battery pack that is detachably attached to the lower part of the handle portion of the device main body 1, and the battery pack 4 houses a plurality of batteries 5 inside.

The batteries 5 are rechargeable Ni-Cd batteries, and each battery 5 is connected in series. Positive and negative terminals 6a and 6b connected to the positive and negative electrodes of the battery 5 are provided on the side surface of the upper part of the cylindrical battery puncture 4 so as to be exposed on the surface of the battery pack 4. Locking portions 7 for detachably attaching the battery pack 4 to the main body of the device are provided on opposite sides of the battery pack 4 .

8 is a charger, which has terminals 6a of the battery pack 4 on the top surface;
A recess 9 is formed into which the portion provided with the 6b is mounted.

FIG. 1 shows a circuit block with a battery pack 4 attached to a charger 8. As shown in FIG. IO is a charging circuit that outputs charging current to charging terminals 11a and llb.

The charging terminals 11a and llb are the terminals 6 of the battery pack 4.
a.

6b. 12 detects that charging of the battery 5 is completed and the battery 5 is fully charged from the voltage of the battery 5, temperature of the battery 5, charging time, etc., and sends a full charge signal to the terminal 13.
This is a charging completion detection means for outputting to.

These charging circuits10. The charging completion detection means 12 is provided in the charger 8.

Reference numeral 14 denotes a full charge information holding means that receives a full charge signal from the charge completion detection means 12 of the charger 8 and holds information that the battery 5 is fully charged. The full charge information holding means 14 is formed of a latch circuit, and when the full charge information signal from the charge completion detection means 12 is input through the input terminal 15a, it outputs a full charge signal to its output terminal 15b. Moreover, once the full charge signal from the charge completion detection means 12 is input, the signal output to the output terminal 15b is maintained until a release signal is input to the reset terminal 15c. The full charge information holding means 14 is housed in the battery bag 4, and each of its terminals 15a, 15
b, 15C is provided to be exposed on the side surface of the protruding upper part of the battery pack 4.

FIG. 2 shows the circuit block with the battery pack 4 attached to the main body 1 of the device. Insert battery pack 4 into device body 1
When installed, the positive and negative terminals 1.6a connected to load 2
, 16b are connected to the positive and negative terminals 6a and 6b of the battery pack 4. The load 2 is connected to the terminals 1.6a and 16b via the power switch 3.
When closed, DC current is supplied from the battery 5 to the load 2.

17 is a remaining capacity detection means for detecting the remaining capacity of the battery 5. The remaining capacity detection means 17 has a positive terminal 16a and a load 2.
It consists of a current detection resistor connected in series between the two, and a microcomputer that serves both as storage means and calculation means.

The remaining capacity detection means 17 generates a voltage according to the discharge current value discharged from the battery 2 by the current detection resistor, A/D converts this voltage, and captures it as data on the amount of discharge discharged from the battery 2. Find the time product of discharge amount.

When the battery pack 4 is attached to the device main body 1, the remaining capacity calculation circuit 17 receives the full charge signal output from the output terminal 15b of the full charge information holding means 14 of the flat battery 4 at its input terminal 18, and Set the stored remaining capacity data to a fully charged state. When the power switch 3 is closed, the battery 5 is connected to the load 2, and the battery 5 is discharged, the remaining capacity detection means 17 sequentially detects the remaining capacity data that was previously set to the fully charged state. The remaining capacity of the battery 5 is determined by subtracting the time product of the required discharge amount. The remaining capacity display section 20 displays the level of the remaining capacity by lighting up a plurality of display bodies 20a made of LEDs in a number corresponding to the remaining capacity determined by the remaining capacity detecting means 17. When the power switch 3 is closed, the power switch 3 outputs a release signal to the signal terminal 19. The release signal is input to the reset terminal 15c of the full charge information holding means I4, and the full charge information holding means 14, which is a latch circuit, stops outputting the full charge signal to the output terminal 15b.

In this embodiment, the charging completion detection means 12 is connected to the charger 8.
Although it is provided in the battery pack 4, it may also be provided in the battery pack 4. In this case, the charging completion detection means 12 and the full charge information holding means 14
The terminals 13.15a provided between the terminals 13 and 15a for receiving and passing the full charge information become unnecessary. In addition, charging completion detection means 1
2 detects the completion of charging of the battery 5 from the battery temperature, the output of a temperature sensor that is placed in close contact with the battery 5 in the battery pack 4 to detect the battery temperature is used to detect the completion of charging in the charger 8. There is also the advantage that there is no need for terminals, wiring, etc. for sending the data to the means I2.

A second embodiment of the present invention will be described based on FIGS. 4 to 7. Note that the same members as those in the first embodiment described above are designated by the same reference numerals in the drawings, and their explanations will be omitted.

FIG. 4 shows the circuit block with the battery pack 4 attached to the charger 8. Reference numeral 21 denotes remaining capacity information holding means consisting of a storage memory in which data can be written and read. The remaining capacity information holding means 21 stores data on the remaining capacity of the battery 5 and holds the remaining capacity information, and is provided in the battery pack 4.

22 is a charging current detection circuit connected to the charging circuit 10, and is formed of a current detection resistor. The charging current detection circuit 22 generates a voltage according to the charging current value output from the charging circuit 10. Reference numeral 23 denotes remaining capacity detecting means consisting of a microcomputer, and the remaining capacity detecting means 23 A/D converts the voltage generated by the charging current detecting circuit 22, and converts the voltage generated by the charging current detecting circuit 22 into data as data on the amount of charge to be charged to the battery 5. and calculate the time product of discharge amount. 24 is a remaining capacity information holding unit 21 for remaining capacity data obtained by the remaining capacity detecting unit 23;
This is a control circuit that controls the timing of writing to and reading the remaining capacity data from the remaining capacity information holding means 21.

When the battery pack 4 is attached to the charging H8, the input terminal 25 of the remaining capacity detection means 23 is connected to the output terminal 26 of the remaining capacity information holding means 21 of the flat battery 4, and the control circuit 24
commands the remaining capacity detection means 23 to read remaining capacity data from the remaining capacity information holding circuit 21. The remaining capacity detection means 23 stores the remaining capacity data read from the remaining capacity information holding means 21. When the charging circuit 10 operates and starts charging the battery 5, the remaining capacity detecting means 23 adds the time product of the charge amount sequentially determined from the previously read remaining capacity data. The remaining capacity of the battery 5 is determined, and data of the remaining capacity determined at the same time is written and updated in the remaining capacity detection means 214. The remaining capacity information holding means 21 holds the remaining capacity of the battery 5 at that time even if charging of the battery 5 is terminated midway.

FIG. 6 is a flowchart showing the processing procedure in the remaining capacity detection means 24 described above. According to this, the remaining capacity detection means 24 first determines whether or not the battery pack 4 is attached to the charger 8, and if a flat battery 4 is attached,
The remaining capacity data B is read from the remaining capacity information holding means 22. When charging starts, it is determined whether or not charging has been completed. If charging is in progress, the charging current is determined based on the voltage generated by the charging current detection circuit 23. Remaining capacity data B that was sampled and read out in advance by calculating the time product of charging current
Add it to find the remaining capacity. Then, this newly obtained remaining capacity data B is written into the remaining capacity information holding means 22. The above process is repeated until charging is completed, and when charging is completed, the process is terminated.

FIG. 5 shows the circuit block with the battery pack 4 attached to the main body l of the device. 27 is a discharge current detection circuit connected between the power switch 3 and the positive terminal 16a, and is formed of a current detection resistor. The discharge current detection circuit 27 generates a voltage corresponding to the discharge current value discharged from the battery 5.

Reference numeral 28 denotes remaining capacity detecting means consisting of a microcomputer, and the remaining capacity detecting means 28 A/D converts the voltage generated by the discharge current detecting circuit 27, and converts the voltage generated by the discharge current detecting circuit 27 into data as data on the discharge amount discharged from the battery 5. and calculate the time product of discharge amount. Reference numeral 29 denotes a control circuit that controls the timing of writing the remaining capacity data determined by the remaining capacity detecting means 28 into the remaining capacity information holding means 22 and the timing of reading the remaining capacity data from the remaining capacity information holding means 22.

When the battery pack 4 is attached to the device body 1, the remaining capacity detecting means 28 has its input terminal 30 connected to the output terminal 26 of the remaining capacity information holding means 21 of the battery pack 4, and the control circuit 29 detects the remaining capacity. The means 28 is instructed to read the remaining capacity data from the remaining capacity information holding circuit 22.

The remaining capacity detection means 28 stores the remaining capacity data read from the remaining capacity information holding means 22. When the power switch 3 is closed and the battery 5 is connected to the load 2 to start discharging the battery 5, the remaining capacity detection means 28 sequentially calculates the remaining capacity from the previously read remaining capacity data. The remaining capacity of the battery 5 is obtained by subtracting the time product of the discharge amount, and the remaining capacity data obtained at the same time is written into the remaining capacity detecting means 22 and updated. The remaining capacity data obtained by the remaining capacity detection means 28 is
It is displayed on the remaining capacity display section 20.

FIG. 7 is a flowchart showing the processing procedure in the remaining capacity detection means 28 described above. According to this, the remaining capacity detecting means 28 consisting of a microcomputer is reset and started when the battery pack 4 is attached to the main body 1 of the device and power is supplied from the battery 5. Remaining capacity detection means 2
8 starts the reset, first, the remaining capacity data B is read from the remaining capacity information holding means 22. Next, it is determined from the voltage generated by the discharge current detection circuit 27 whether the discharge current 1° is zero, that is, whether the battery 5 is being discharged. When the discharge current is not zero, that is, when the battery 5 is being discharged, the discharge current is sampled from the voltage generated by the discharge current detection circuit 27, and the time product of this discharge current is determined and read out in advance. Subtract it from the remaining capacity data B to find the remaining capacity. Then, this newly obtained remaining capacity data B is written into the remaining capacity information holding means 22, and the remaining capacity is displayed on the remaining capacity display section 2o.

In addition, in the step of determining the discharge current, if the discharge current is zero, it means that the battery bag 4 is left attached to the device main body 1 without being worked on. From the self-discharge rate α, the self-discharge amount α・d
t is subtracted from the remaining capacity data B, and thereafter, the data in the remaining capacity information holding means 22 is updated in the same way as during discharging, and the remaining capacity is displayed on the remaining capacity display section 2o.

In the second embodiment described above, the remaining capacity information holding means 22 is formed of a storage memory and power is supplied from the battery 5, so that when the remaining capacity of the battery 5 becomes low, the motor as the load 2 When an overload is applied and the motor locks, the battery voltage drops rapidly, making it impossible to secure the power supply voltage for the remaining capacity information holding means 21 and the remaining capacity detecting means 28.
The remaining capacity information holding means 21 is reset, and the stored remaining capacity data disappears. Therefore, the motor lock is released, the battery voltage rises, the remaining capacity detection circuit 28 is reset and started, and the remaining capacity information holding means 2
When the remaining capacity data is read from 1, the remaining capacity data in the remaining capacity information holding means 21 is zero, even though there is actually still capacity remaining. Since the capacity is calculated, a problem arises in that the actual remaining capacity and the displayed remaining capacity are different.

Therefore, if the remaining capacity information holding means 21 is formed of a non-volatile memory, even if the voltage of the battery 5 drops due to motor lock, the non-volatile memory retains the data, so the actual remaining capacity and remaining capacity It is possible to prevent the remaining capacity displayed on the display unit from being different from the remaining capacity, and reliability can be improved. Furthermore, since nonvolatile memory requires power only when writing data, it saves power and can effectively utilize the battery 5.

〔Effect of the invention〕

Since the battery remaining capacity display device for a rechargeable device according to the present invention is configured as described above, it has the following effects.

In the device described in claim (1), a charging completion detection means is provided in the charger or the battery pack, a full charge information holding means is provided in the battery pack, and a remaining capacity detection means is provided in the main body of the device, so that the device is fully charged. When a battery pack is attached to the main body of the device, information indicating that the battery is fully charged is passed from the full charge information holding means of the battery pack to the remaining capacity detecting means of the main body of the device. In order to detect the remaining capacity by subtracting the amount of discharge due to battery discharge from the remaining capacity of the battery as the full charge capacity, the remaining capacity when the battery pack is attached to the device body and the battery is discharged is calculated. can be displayed accurately.

The device described in claim (2) is provided with a remaining capacity detecting means for determining the remaining capacity of the battery from the amount of charge or discharge of the battery, and a remaining capacity information holding means for holding remaining capacity information. By providing this in the battery pack, during charging, the remaining capacity information from the remaining capacity information holding means of the battery pack is passed to the remaining capacity detecting means of the charger, and the remaining capacity detecting means detects the battery from the remaining capacity information. The remaining capacity is detected by adding up the amount of charge due to charging, and when the battery pack is attached to the device,
The remaining capacity information from the remaining capacity information holding means of the battery pack is
The remaining capacity detection means subtracts the discharge amount due to battery discharge from the remaining capacity information to detect the remaining capacity, so the remaining capacity of the battery during charging is also detected. can be displayed accurately.

In addition to the above-mentioned effects, the device described in claim (3) can prevent the actual remaining capacity from being different from the remaining capacity displayed on the remaining capacity display section, and also saves power and makes the battery more efficient. available for use.

[Brief explanation of the drawing]

1 and 2 are block circuit diagrams of the first embodiment of the present invention in different connection states, and FIGS. 3(a) and 3(b)
), (C) are external views of the charger, battery pack, and device body, respectively; FIGS. 4 and 5 are block circuit diagrams of the second embodiment of the present invention in different connection states; FIGS. Figure 7 shows
7 is a flowchart of different remaining capacity detection means. ■ Stage, 17 21-・ Means, device body, 2- Load, Battery pack, 5- Battery, 6.7- = Positive and negative terminals, Charger, 10- Charging circuit, Charging completion detection means, 14- Full charge information Retainer remaining capacity detection means, remaining capacity display section, remaining capacity information holding means, 23.28-Remaining capacity detection patent applicant Matsushita Electric Works Co., Ltd. agent Patent attorney Toshimaru Takemitsu (2 persons) Fig. 1 Fig. 2 Figure Left Figure N/:) Figure 7 Procedural Amendments December 4, 1991

Claims (3)

[Claims] (1) A battery pack containing a rechargeable battery and having positive and negative terminals connected to the battery; and a device body to which the battery pack is detachably attached and a load supplied with power from the battery; and a charger equipped with a charging circuit that supplies charging current to the batteries of the battery pack. charging completion detection means for detecting that the battery is fully charged; full charge information holding means for retaining information that the battery is fully charged; and remaining capacity determining means for determining the remaining capacity of the battery from the amount of discharge of the battery. a detection means, a remaining capacity display section that displays remaining capacity;
, the charge completion detection means is provided on the charger or the battery pack, the full charge information holding means is provided on the battery pack, and the remaining capacity detection means and the remaining capacity display section are provided on the main body of the device. Capacity display device. (2) a battery pack containing a rechargeable battery and having positive and negative terminals connected to the battery; and a device body to which the battery pack is detachably attached and a load supplied with power from the battery; In a remaining battery capacity display device for a rechargeable device, which is formed by combining a charger equipped with a charging circuit that supplies charging current to the batteries of the battery pack, the remaining capacity of the battery is determined from the amount of charge or discharge of the battery. The battery includes a remaining capacity detecting means, a remaining capacity information holding means for holding remaining capacity information of the battery, and a remaining capacity display section for displaying the remaining capacity, and the remaining capacity detecting means is provided on the charger and the device main body, and the remaining capacity detecting means is provided on the charger and the device body, A battery remaining capacity display device for a rechargeable device, comprising a capacity information holding means provided on a battery pack and a remaining capacity display section provided in the main body of the device. (3) The battery remaining capacity display device for a rechargeable device according to claim (2), wherein the remaining capacity information holding means is formed of a nonvolatile memory.