JP2932872B2 - Battery level display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for displaying the remaining capacity of a secondary battery which supplies power to a portable electronic device.

[0002]

2. Description of the Related Art Battery capacity remaining amount display devices include a battery voltage detection method which is advantageous in terms of cost and an electric quantity integration method with high display accuracy, and most of the display devices are built in a portable device body or a battery pack. Has been used.

[0003] Hereinafter, a conventional device for displaying the remaining capacity of the electric quantity integrating method will be described with reference to the drawings.

FIG. 4 is a block diagram showing a conventional capacity remaining amount display device. 4, reference numeral 1 denotes a secondary battery, and 2 denotes a current detection resistor, which is connected to the negative terminal of the secondary battery 1. Reference numeral 3 denotes a charge / discharge current detecting means, which comprises an operational amplifier 31 for detecting a charging current and an operational amplifier 32 for detecting a discharging current to which a minute voltage generated at both ends of the current detecting resistor 2 is input. Reference numeral 4 denotes a voltage drop detecting means which uses the terminal voltage of the secondary battery 1 as a signal input. Reference numeral 5 denotes a temperature detecting means for detecting an ambient temperature of the secondary battery 1. Numeral 6 denotes an electric quantity calculating means to which the signal outputs of the operational amplifiers 31 and 32 and the signal output of the temperature detecting means 5 are inputted. Reference numeral 7 denotes a charge completion detection unit to which the signal output of the operational amplifier 31 is input. Reference numeral 9 denotes a capacity storage unit to which a signal output of the electric quantity integrating unit 10 described below is input. Reference numeral 10 denotes an electric quantity integrating means, which receives as input the signal output of the electric quantity calculating means 6, the signal output of the capacity storing means 9, the signal output of the voltage drop detecting means 4, and the signal output of the charging completion detecting means 7. Reference numeral 11 denotes a display unit to which a signal output of the electric quantity integrating unit 10 is input. Reference numeral 12 denotes a microcomputer, which electrically constitutes the electric quantity calculating means 6, the charging completion detecting means 7, the capacity storing means 9, and the electric quantity integrating means 10. A terminal 13 is connected to a portable device or a charger at both ends.

The operation of the conventional battery remaining amount display device configured as described above will be described below.

First, the operation at the time of charging will be described. When a charger is connected to the terminal 13 and charging is started, a negative minute voltage (when the negative electrode of the secondary battery 1 is set to zero potential) is generated at both ends of the current detection resistor 2 in proportion to the charging current. This minute voltage is amplified to a positive value by the operational amplifier 31 and is output as a signal to the electric quantity calculating means 6 and the charging completion detecting means 7. The electric quantity calculating means 6 calculates the electric quantity by multiplying the charging current value output from the operational amplifier 31 by a predetermined time, and further calculates the electric quantity by the charging current and the temperature information output from the temperature detecting means 5. Multiplied by the charging efficiency determined by
Output signal to The charging completion detecting means 7 includes an operational amplifier 31
The output is reset when a charging current signal is input, and the charging current is changed from rapid charging to trickle charging as the charging proceeds, and the output is set upon recognizing the completion of charging. The electric quantity integrating means 10 integrates the electric quantity by adding the charged electric quantity output from the electric quantity calculating means 6 at every predetermined time, and a ratio of the accumulated electric quantity value to the storage value of the capacity storage means 9. And when the output of the charging completion detecting means 7 is set, the capacity at the time of charging is updated by using the integrated value of the amount of electricity at that time as the storage value of the capacity storage means 9. To 100
Set to%.

[0007] Based on the remaining amount information determined by the electric quantity accumulating means 10, the display means 11 displays the LC information as shown in FIG.
The remaining amount is gradually displayed on the D display, and the display sequentially shifts from the display level (1) to (6) as the charging progresses. Here, FIG. 3A is a diagram showing the relationship between the remaining capacity of the battery and the display level. LCD display is 5
Segments are arranged in a row, and the remaining amount is 0% ~
One LCD blinks for 10%, one LCD lights when the remaining value is 10% to 20%, the LCD lights at 20% intervals after the remaining value of 20%, and the remaining capacity value of the battery is displayed by stick-shaped lighting. Always display.

Next, the operation at the time of discharging will be described. When a portable device is connected to the terminal 13 and used, current is supplied from the secondary battery 1 to start discharging. As a result, both ends of the current detection resistor 2 have a positive small voltage (2
(When the negative electrode of the secondary battery 1 is set to zero potential). This minute voltage is amplified by the operational amplifier 32 and output to the electric quantity calculating means 6. The electric quantity calculating means 6 calculates the electric quantity by multiplying the discharge current value outputted from the operational amplifier 32 by a predetermined time, and further calculates the electric quantity by the magnitude of the discharge current and the temperature information outputted from the temperature detecting means 5. The final discharge quantity is multiplied by the determined discharge efficiency, and this is output as a signal to the quantity integrating means 10. Here, the voltage drop detection means 4
It basically consists of a voltage comparator and monitors the voltage drop of the secondary battery 1 as the discharge progresses, and this detection voltage is set higher than the operation stop voltage of the portable device. The electric quantity integrating means 10 integrates the electric quantity by subtracting the discharged electric quantity which is output as a signal from the electric quantity calculating means 6 at every predetermined time, and stores the electric quantity integrated value in the capacity storage means 9. The remaining value is determined based on the ratio to the voltage, and when the voltage drop signal is output from the voltage drop detecting means 4, the storage value of the capacity storage means 9 is corrected from the difference between the integrated electric quantity value at that time and the integrated value zero. To update the discharge capacity. Next, this electric quantity integrated value is set to zero, and the remaining capacity value is set to 0%. Specifically, assuming that the integrated amount of electricity when the voltage drop signal is output from the voltage drop detection means 4 is a value corresponding to the remaining capacity value of 5%, the storage value of the capacity storage means 9 is set to 5
If the integrated value of the amount of electricity when the voltage drop signal is output is a negative value obtained by subtraction and is a value corresponding to the remaining amount value −5%, the storage value of the capacity storage unit 9 is calculated. Is increased by 5%. The display means 11 performs the operation shown in FIG. 3 based on the remaining capacity information determined by the electric quantity integrating means 10.
As shown in (a), the remaining capacity is displayed in a step-by-step manner on a display comprising an LCD, and the display sequentially shifts from a display level (6) to (1) as the discharge proceeds.

Finally, the operation during standby will be described. The standby state refers to a state in which neither a portable device nor a charger is connected to the terminal 13, or a state in which a discharge current or a charge current does not flow even when the terminal 13 is connected. Accordingly, the recognition at the time of standby is performed by detecting that the outputs of the operational amplifiers 31 and 32 are both zero by the electric quantity calculating means 6.

In the electric quantity calculating means 6, information on the self-discharging electric quantity of the secondary battery 1, which is measured in advance for each temperature, the electric power consumption of the battery remaining amount display device, and the temperature information outputted as a signal from the temperature detecting means 5. From this, the amount of discharge electricity during standby is determined. The subsequent operation is the same as the operation at the time of the discharge, and a detailed description thereof will be omitted.

[0011]

As described above, in the conventional battery remaining amount display device of the electric quantity integrating method, the electric charge amount and the electric discharge amount (including the standby state) are measured by the magnitude of the charge / discharge current and the temperature. The remaining capacity level is determined and displayed by comparing the integrated value with the stored value which is the latest capacity at that time by adding and subtracting this value during charging and subtracting during discharging.

Therefore, it is important to update the stored value to an accurate value in order to enhance the display accuracy. By the way, the updating of the stored value is performed by the detection of the completion of charging or the detection of the voltage drop. Since the error between the integrated value of electric quantity (display value) and the actual remaining capacity value increases due to the error,
In such a situation, updating the stored value does not result in accurate updating of the capacity, and there is a problem that the display accuracy cannot be improved.

The present invention solves the above problems,
An object of the present invention is to provide a battery remaining amount display device capable of updating a stored value of a correct capacity.

[0014]

In order to achieve the above object, a battery remaining amount display device according to the present invention comprises a current detecting resistor for converting a charging / discharging current of a secondary battery into a minute voltage; Charge / discharge current detecting means for amplifying the minute voltage generated at both ends by the operational amplifier for charging and the operational amplifier for discharging, respectively, and outputting the result as a signal, respectively, and the voltage of the secondary battery has become lower than a predetermined voltage value. Voltage drop detecting means for detecting that the temperature of the secondary battery has been detected and outputting the result as a signal; and charging current output, discharging current output of the charging / discharging current detecting means and the temperature detecting means. The output is used as an input to determine the state of charge, discharge or standby, an amount of electricity calculation means for calculating the amount of electricity at that time, and a signal output is set by detecting the completion of charging of the secondary battery. signal Charge completion detection means for resetting a force, and when the signal output of the charge completion detection means is in a set state and the output of the electricity quantity calculation means is in a discharge state, integration of the discharge electricity quantity is performed at every predetermined time, When the signal output of the charging completion detecting means is in a reset state, the discharging electric quantity integrating means for making the integrated value zero regardless of the output of the electric quantity calculating means, and the signal output of the charging completion detecting means is in a set state. A capacity storage means for storing the integrated value of the discharged electric quantity integrating means as the latest battery capacity when the first voltage drop signal is output from the voltage drop detecting means after the charging; and When the signal output of the amount calculating means is the charged amount of electricity, the amount is added, and when the signal output is the amount of discharged electricity, the amount is subtracted to integrate the amount of electricity. In addition to determining the value, when the voltage drop signal is output for the first time after charging from the voltage drop detection means, the integrated value of the amount of electricity is set to a value corresponding to the remaining capacity value at the predetermined voltage value, and charging is performed. When the signal output of the charging completion detecting means is in the set state, the electric quantity integrating means sets the electric quantity integrated value to a value corresponding to 100% of the remaining quantity, and the remaining quantity determined by the electric quantity integrating means. Display means for displaying the remaining amount stepwise based on the value.

The electric quantity calculating means determines the state of charge, discharge, or standby, and in the case of charge or discharge, multiplies the charge current output value or discharge current output value by a predetermined time to calculate the electric quantity. Calculate and multiply the charge amount or the discharge efficiency determined by the charge current output value or the discharge current output value and the battery temperature by the amount of electricity to obtain the final amount of electricity. It is preferable to select data corresponding to the temperature from the data on the amount of self-discharged electricity of the secondary battery and the amount of consumed electricity of the remaining amount display device to obtain the amount of electricity.

[0016]

With such a configuration, the amount of discharge electricity when the battery is discharged without recharging from the charge completion state to the detection of the first voltage drop signal is integrated by the discharge electricity amount integrating means, By storing this integrated value as the latest capacity in the capacity storage means, it is possible to accurately update the latest capacity of the battery.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a secondary battery, and reference numeral 2 denotes a current detection resistor, which is connected to a negative terminal of the secondary battery 1. Reference numeral 3 denotes a charge / discharge current detecting means, which comprises an operational amplifier 31 for detecting a charging current and an operational amplifier 32 for detecting a discharging current to which a minute voltage generated at both ends of the current detecting resistor 2 is input. Reference numeral 4 denotes a voltage drop detecting means to which the terminal voltage of the secondary battery 1 is input. Reference numeral 5 denotes a temperature detecting means for detecting an ambient temperature of the secondary battery 1. Numeral 6 denotes an electric quantity calculating means to which the signal outputs of the operational amplifiers 31 and 32 and the signal output of the temperature detecting means 5 are inputted. Reference numeral 7 denotes a charge completion detection unit to which the signal output of the operational amplifier 31 is input. Reference numeral 8 denotes a discharge electricity amount integrating means, which receives a signal output of the electricity amount calculating means 6 and a signal output of the charge completion detecting means 7 as inputs. Reference numeral 9 denotes a capacity storage unit to which the signal output of the voltage drop detecting unit 4, the signal output of the charging completion detecting unit 7 and the signal output of the discharged electricity amount integrating unit 8 are input. Reference numeral 10 denotes an electric quantity integrating means, which receives as input the signal output of the electric quantity calculating means 6, the signal output of the capacity storing means 9, the signal output of the voltage drop detecting means 4 and the signal output of the charging completion detecting means 7. Reference numeral 11 denotes a display unit to which a signal output of the electric quantity integrating unit 10 is input. 1
Reference numeral 2 denotes a microcomputer, which constitutes a circuit corresponding to the electric quantity calculating means 6, the charging completion detecting means 7, the discharged electric quantity integrating means 8, the capacity storing means 9, and the electric quantity integrating means 10. 1
3 is a terminal to which a portable device or a charger is connected.

The operation of the battery remaining amount display device of the present invention configured as described above will be described below.

First, the operation at the time of charging will be described. When a charger is connected to the terminal 13 and charging is started, a negative minute voltage (when the negative electrode of the secondary battery 1 is set to zero potential) is generated at both ends of the current detection resistor 2 in proportion to the charging current. This minute voltage is amplified to a positive value by the operational amplifier 31 and is output as a signal to the electric quantity calculating means 6 and the charging completion detecting means 7. The electric quantity calculating means 6 calculates an electric quantity by multiplying the charging current value output from the operational amplifier 31 by a predetermined time, and further calculates the electric quantity by the magnitude of the charging current and the temperature information output from the temperature detecting means 5. The final charge amount is multiplied by the determined charge efficiency, and a signal is output to the charge amount integrating means 10. The charging completion detecting means 7 resets the signal output by inputting the charging current signal from the operational amplifier 31, and recognizes the completion of charging by changing the charging current value from rapid charging to trickle charging as the charging proceeds. To set the signal output. The electric quantity integrating means 10 integrates the electric quantity by adding the charged electric quantity outputted as a signal from the electric quantity calculating means 6 at every predetermined time, and stores the electric quantity integrated value in the capacity storage means 9. The remaining capacity value is determined based on the ratio of the remaining charge to the total amount of electricity, and when the signal output of the charging completion detection means 7 is in the set state, the integrated amount of electricity is set to a value corresponding to 100% of the remaining capacity. The display means 11 displays the remaining amount information shown in FIG.
As shown in (a), the remaining capacity is displayed step by step on an LCD display, and the display sequentially shifts from the display level (1) to (6) as charging progresses.

Next, the operation at the time of discharging will be described. When a portable device is connected to the terminal 13 and used, current is supplied from the secondary battery 1 to start discharging. As a result, both ends of the current detection resistor 2 have a positive small voltage (2
(When the negative electrode of the secondary battery 1 is set to zero potential). This minute voltage is amplified by the operational amplifier 32 and output as a signal to the electric quantity calculating means 6. The electric quantity calculating means 6 calculates the electric quantity by multiplying the discharge current value outputted from the operational amplifier 32 by a predetermined time, and further calculates the electric quantity by the magnitude of the discharge current and the temperature information outputted from the temperature detecting means 5. The final discharge electricity quantity is multiplied by the determined discharge efficiency, and this is output as a signal to the discharge electricity quantity integrating means 8 and the electricity quantity integrating means 10. The discharged electricity amount integrating means 8 integrates the discharged electricity amount at every predetermined time only when the signal output of the charging completion detecting means 7 is in the set state and the signal output of the electricity amount calculating means 6 is in the discharging state. When the signal output of the charging completion detecting means 7 is in a reset state, the integration of the discharged electric quantity is set to zero regardless of the output of the electric quantity calculating means 6. Here, the voltage drop detecting means 4 basically comprises a voltage comparator, monitors the voltage drop of the secondary battery 1 as the discharge proceeds, and sets this detection voltage higher than the operation stop voltage of the portable device. Have been. When the signal output of the charge completion detecting means 7 is set and the first voltage drop signal after charging is output from the voltage drop detecting means 4 when the signal output of the charge completion detecting means 7 is set, the capacity storage means 9 stores the integrated value of the discharge electric quantity integrating means 8 in the latest battery capacity. To be stored. In addition, the electric quantity integrating means 10 integrates the electric quantity by subtracting the discharged electric quantity signal output from the electric quantity calculating means 6 at every predetermined time, and stores the electric quantity integrated value in the capacity storage means 9. The remaining capacity value is determined based on the ratio to the value, and when the voltage drop signal is output from the voltage drop detecting means 4, the integrated value of the electric quantity is set to zero. The display means 11 displays the remaining amount information shown in FIG.
As shown in (a), the remaining capacity is displayed in a step-by-step manner on a display comprising an LCD, and the display sequentially shifts from a display level (6) to (1) as the discharge proceeds.

Next, the operation of the apparatus during standby will be described. Since no charge / discharge current flows during standby, the outputs of the operational amplifiers 31 and 32 are both zero, and the electric quantity calculation means 6 recognizes the standby state by detecting this.
The electric quantity calculating means 6 calculates a standby discharge based on the self-discharged electric quantity of the battery 1 measured in advance for each temperature, the information on the electric power consumption of the battery remaining amount display device, and the temperature information output from the temperature detecting means 5. Determine the quantity of electricity. The subsequent operation is the same as the operation at the time of the discharge, and a detailed description thereof will be omitted.

FIG. 2 shows a one-chip microcomputer 12 comprising an electric quantity calculating means 6, a charging completion detecting means 7, a discharging electric quantity integrating means 8, a capacity storing means 9 and an electric quantity integrating means 10 of this embodiment.
6 is a control flowchart of the microcomputer unit in the case of the configuration of FIG. The operation of each step in FIG. 2 is basically the same as the above-described operation, and a detailed description thereof will be omitted.

FIG. 3B is a diagram showing the relationship among the battery voltage, charge / discharge current, and display level during charge / discharge. The display level sequentially shifts from (1) to (6) by charging, and the remaining amount is set to 100% upon completion of charging. On the other hand, at the time of discharging, the display level sequentially shifts from (6) to (1), and the output of the voltage drop detection signal indicates that the remaining capacity value is set to 0%.

As described above, according to the present embodiment, the discharged electric quantity integrating means 8 sequentially accumulates the electric quantity at the time of discharging without recharging from the charged completed state, and the capacity storage means 9 stores the charged completed state. Only when the first voltage drop signal is detected after charging without recharging, the integrated value of the discharged electricity amount integrating means 8 is stored as the latest battery capacity. Does not accumulate the amount of discharged electricity and store the battery capacity. Therefore, the stored value after the capacity update is accurate, and the display accuracy can be improved.

[0026]

As described above, according to the present invention, the amount of electricity when discharged without recharging from the fully charged state is sequentially integrated, and the first voltage after charging without recharging from the fully charged state is obtained. The integrated value of the amount of discharged electricity is stored as the latest battery capacity only when a decrease signal is detected, and when recharging is performed during discharging from the fully charged state, the integrated amount of discharged electricity and the storage of the battery capacity are not performed. Therefore, it is possible to accurately store the latest capacity of the battery, and it is possible to provide a battery remaining amount display device with high display accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a battery remaining amount display device according to an embodiment of the present invention.

FIG. 2 is a control flowchart of a microcomputer unit according to an embodiment of the present invention.

FIG. 3A is a diagram illustrating a relationship between a remaining capacity and a display level. FIG. 3B is a diagram illustrating a relationship between a battery voltage, a charge / discharge current, and a display level during battery charge / discharge.

FIG. 4 is a block diagram of a conventional battery level display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Current detection resistor 3 Charge / discharge current detection means 4 Voltage drop detection means 5 Temperature detection means 6 Electric quantity calculation means 7 Charge completion detection means 8 Discharge electric quantity integration means 9 Capacity storage means 10 Electric quantity integration means 11 Display Means 12 Microcomputer 13 Terminal

Claims (3)

(57) [Claims] 1. A current detecting resistor for converting a charging / discharging current of a secondary battery into a minute voltage, and a minute voltage generated at both ends of the current detecting resistor are amplified by a charging operational amplifier and a discharging operational amplifier, respectively. Charge / discharge current detection means for outputting the result as a signal, voltage drop detection means for detecting that the voltage of the battery has fallen below a predetermined voltage value, and detecting the temperature of the battery and outputting the result as a signal Temperature detection means, and performs charge / discharge / standby state determination using the charge current output, discharge current output of the charge / discharge current detection means and the signal output of the temperature detection means as inputs, and calculates the quantity of electricity at that time Electricity quantity calculation means, charge completion detection means for setting a signal output by detecting the completion of charging of the battery, and resetting the signal output by starting charging, the charge completion detection means When the signal output is in the set state and the signal output of the electric quantity calculating means is in the discharging state, the electric quantity of discharge is integrated every predetermined time, and when the signal output of the charging completion detecting means is in the reset state, the electric quantity is calculated. A discharge amount integrating means for reducing the integrated value to zero irrespective of the signal output of the calculating means; and a voltage drop signal for the first time after charging is output from the voltage drop detecting means with the signal output of the charging completion detecting means being set. Capacity storage means for storing the integrated value of the discharged electricity amount integrating means as the latest battery capacity when the signal output is performed, and adding and discharging when the signal output of the electricity amount calculating means is in a charged state at every predetermined time. In the case of, the amount of electricity is integrated by subtraction, the remaining capacity value is determined by the ratio to the stored value of the capacity storage means, and the first voltage after charging is determined by the voltage drop detection means. When the lower signal is output, the integrated value of the amount of electricity is set to a value corresponding to the remaining capacity value at the predetermined voltage value, and when the signal output of the charging completion detecting means is set by charging, An electric quantity integrating means for setting the electric quantity integrated value to a value corresponding to the remaining capacity of 100%; and a display means for displaying the remaining capacity stepwise based on the remaining quantity value determined by the electric quantity integrating means. Battery level display device provided. 2. An electric quantity calculating means judges a state of charging, discharging or standby, and in the case of charging or discharging, calculates an electric quantity by multiplying a charging current output value or a discharging current output value by a predetermined time. In addition, the charge amount or the discharge efficiency determined by the charge current output value or the discharge current output value and the battery temperature are multiplied by the amount of electricity to obtain a final amount of electricity. 2. A structure according to claim 1, wherein data corresponding to the temperature is selected from the data on the amount of electric discharge and the amount of electric power consumed by the remaining amount display device and used as the amount of electric power.
Battery level display device according to the above. 3. The battery remaining amount display device according to claim 1, wherein the means for displaying the remaining capacity stepwise comprises a display having a plurality of LCDs which are turned on or off by a signal input.