JPH0659001A - Calculation device for remaining operating time of battery - Google Patents

Abstract

PURPOSE:To avoid such a situation that an actual discharging time is shorter than an indicated value of remaining service time by calculating the means value of plural operating times stored in a memory means. CONSTITUTION:When a shaving switch 3 is turned on and a motor 2 starts driving, an absolute value circuit 6 outputs a voltage and polarity signal which correspond to the discharge current of drive current battery 1. A V/F converter 7 outputs the pulse of a frequency proportional to a voltage to a counter 8b. When the counter 8a counts pulses of the number comparable to 10% of compensation capacity, the counter 8a outputs an interrupt signal to an FIFO (memory means) 10 and a timer 9. Every time when the interrupt signal is outputted, a calculation means 11a for mean time of CPU 11 calculates a mean time TAVE, and a calculation means 11b for a full time calculates a total time TFUL. Then, a calculation means 11c for a remaining operating time performs calculation the remaining operating time TREM every the seconds, for example, while the switch 3 remains turned on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention calculates the remaining usable time of a battery, which accurately calculates the dischargeable time that changes with the discharge of the battery, that is, the remaining used time in consideration of the magnitude of the discharge current of the battery. Regarding the device.

[0002]

2. Description of the Related Art In an electronic / electrical device, such as a shaving device, in which a rechargeable battery (secondary battery) is incorporated as a power source, the time until charging is required, that is, the remaining capacity of the battery. The dischargeable time (remaining usage time) is one of the items of concern to the user. By grasping this remaining usage time, for example, it is possible to avoid the situation where the battery capacity runs out during use and shaving is interrupted.

As a conventional device for indirectly knowing the remaining usage time, a structure for displaying the remaining capacity of a battery is known. For example, Japanese Patent Application Laid-Open No. 62-272827 discloses a device that calculates the charge / discharge amount of a battery by measuring the charge / discharge time and displays the calculation result as a bar graph. Also, West German Patent Application Publication No. 231356
No. 6 describes a device that measures the charging current / discharging current of a battery and determines the charging / discharging amount of the battery based on the measurement result.

Even when the remaining capacity of the battery is displayed by using these techniques, it is very difficult to predict how much time the battery can be used from this remaining capacity, that is, the remaining usage time. Therefore, it is conceivable to obtain the remaining usage time by dividing the remaining capacity by a predetermined coefficient (for example, average discharge current).

[0005]

[Problems to be Solved by the Invention] For example, the nominal capacity is 60
For a 0mAh battery, set the discharge capacity allowed when charging is completed.
Assume 500mAh (compensation capacity). When the average discharge current (coefficient) during shaving is 700 mA, the remaining usage time after completion of charging is about 42 minutes. That is, when the shaving apparatus is used for 42 minutes (discharged with a current of 700 mAh) after completion of charging, the remaining usage time display decreases from 42 minutes to 0 minutes.

However, in the shaving apparatus,
The load varies depending on the usage pattern. For example, if the shaving device has a trimmer function, using this trimmer function makes the load of the motor heavier than when shaving, and the motor drive current, that is, the discharge current of the battery, is about 1.5 times that when shaving. Become. Further, in order to clean the shaving device, when the blade is removed and the motor is driven, the load on the motor becomes lighter than that during shaving, and the discharge current of the battery becomes about half that during shaving.

When the discharge current of the battery is larger than the average discharge current of 700 mA, the actual time when the shaving apparatus can be used is shorter than 42 minutes, and when it is smaller than 700 mAh,
It will be longer than 42 minutes. This means that the process of shifting the remaining usage time from 42 minutes to 0 minutes is not proportional to the absolute time 42 minutes, and when the load is heavy, the remaining usage time is from 0 minutes to 42 minutes in a time shorter than the absolute time 42 minutes. Shift to minutes,
When the load is light, the remaining usage time shifts from 42 minutes to 0 minutes in a time longer than the absolute time 42 minutes. Specifically, the discharge current greatly differs between the usage pattern in which the trimmer function is frequently used and the usage pattern in which the trimmer function is not used. That is, the total time is different. Conventionally, such fluctuations and magnitudes of the discharge current were not taken into consideration, and in each case, the remaining usage time was calculated based on the uniformly assumed average discharge current. There has been a problem that the dischargeable time does not match, that is, the dischargeable time (actual use) is shorter than the remaining usage time.

[0008]

The object and summary of the present invention is to accurately calculate the total time required for discharging the capacity after the charging is completed in consideration of the fluctuation of the discharge current of the battery, and as a result, the remaining usage time which changes with the discharging. The present invention provides a device for accurately calculating, and for calculating the remaining usage time of a battery, which can avoid the situation where the battery can actually be discharged (used) for a time shorter than the value indicated by the remaining usage time.

A feature of the present invention is that a battery having a compensation capacity which is regarded as a capacity at the time of completion of charging, a time measuring means for measuring a use time of the battery after the charging is stopped, and a discharge capacity at the time of use of the battery are An integrating means for integrating and the integrating means each time the integrating of the reference capacity which is a part of the compensation capacity is completed,
Storage means for storing a plurality of the use times clocked by the timekeeping means, average time calculation means for calculating an average value of the plurality of use times stored in the storage means, and the reference capacity equal to the compensation capacity A total time calculating means for calculating a total time with respect to the compensation capacity by multiplying the constant value, which is a multiplication factor, by the average value; and a proportional value showing a ratio of the compensation capacity and the discharge capacity and the total time. And a remaining usage time calculating means for calculating the remaining usage time. A further feature of the present invention is that the resistance inserted in series with the battery and the absolute value of the voltage generated in the resistance based on the current flowing through the resistance are detected, and a pulse having a frequency corresponding to the voltage is detected. And a converter for outputting, and the integrating of the discharge capacity by the integrating means is realized by counting the pulses. A further feature of the present invention is that it has a time display section for displaying the remaining usage time. A further feature of the present invention is that the integrating means integrates the charge capacities of the batteries during charging.

The time measuring means measures the usage time after the charging of the battery is stopped. At the same time, the discharge capacity of the battery is integrated by the integrating means. Then, the accumulating means is a fixed ratio based on the compensation capacity of the battery, for example, the compensation capacity 50
When 0 mAh is taken as 100%, each time the reference capacity 50 mAh corresponding to 10% of the compensation capacity is counted, the storage means stores the use time measured by the time measuring means. On the other hand, the average time calculating means calculates an average value of the plurality of use times stored in the storage means at a preset predetermined cycle, and the total time calculating means multiplies the average value by a constant. Calculate the total time that is the value. The total time reflects the latest usage time required to discharge the reference capacity, and therefore has a content corresponding to the magnitude of the actual discharge current. Further, the remaining usage time calculating means calculates the ratio of the counting result of the integrating means to the compensation capacity, and calculates the remaining usage time which is a product of the ratio and the total time. Since the total time corresponds to the magnitude of the actual discharge current, the remaining usage time also reflects the value of the actual discharge current. Therefore, the value indicating the remaining usage time can always indicate the content corresponding to the absolute time when the battery can be actually used.

[0011]

1 is a block diagram of the apparatus of the present invention.
In the device shown in the figure, the negative output terminal of a rechargeable battery 1 such as a Ni-Cd battery is grounded, and the positive output terminal is one end of a motor 2 for driving a shaving blade and one end of a shaving switch 3. It is connected to the. The other end of the motor 2 is connected to the collector of the transistor Tr. The base of the transistor Tr is the shaving switch 3 via the resistor R.
Is connected to the other end, and the emitter is grounded via a resistor Rs for detecting a motor current. Further, the positive output terminal of the battery 1 is connected to the positive output of the charging circuit 5 via the charging switch 4, and the negative output of the charging circuit 5 is connected to the emitter of the transistor Tr. For example, an AC power supply is connected to the input side of the charging circuit 5.

The input side of the absolute value circuit 6 is connected to the emitter of the transistor Tr. The absolute value circuit 6 changes the absolute value of the voltage generated in the resistor Rs, that is, the direction of the current flowing through the resistor Rs as the battery 1 is discharged and charged, and changes the polarity of the voltage generated in the resistor Rs. It is a circuit that always outputs a positive value. The absolute value circuit 6 outputs a voltage generated in the resistor Rs and a polarity signal indicating the polarity of this voltage. The voltage is output to the voltage / frequency (V / F) converter 7.

The V / F converter 7 is a circuit for outputting a pulse having a frequency corresponding to the voltage. The V / F converter 7 is, for example, 18 V when the compensation capacity (500 mAh) of the battery 1 is discharged.
It outputs 0000 pulses, and when the capacity (50 mAh) corresponding to 10% of the compensation capacity is discharged, 18000 pulses are output. Similarly, when charging the battery 1, V /
The F converter 7 outputs 180,000 pulses when it is charged with 500 mAh, and outputs 18,000 pulses when it is charged with 50 mAh.

The pulse output from the V / F converter 7 is input to a counter (integrating means) 8b via a frequency divider 8a.
The polarity signal from the absolute value circuit 6 is input to the counter 8b. The frequency divider 8a is a circuit for performing control to divide the frequency of the pulse output from the V / F converter 7 into 1/180. Specifically, each time the V / F converter 7 outputs 180 pulses, it outputs one pulse to the counter 8b.

When the polarity signal indicates "+", the counter 8b adds the pulse counting result (U
P) and shows "-", it is a circuit for subtracting (DOWN) the counting result of the pulse. The counter 8b counts a preset number of pulses each time a timer (time measuring means) 9 and a FIFO (First In First Out motor current d).
An interrupt signal is output to ata buffers (storage means) 10. The preset number is, for example, 10% of the compensation capacity when the compensation capacity of the battery 1 is 500 mAh.
A number indicating that mAh has been discharged, specifically 100 pulses.

The timer 9 is a circuit for measuring the time when the shaving switch 3 is set to ON, that is, the drive time of the motor 2 in seconds, and the time measurement result (TUS) is stored in the FIFO 10 each time the interrupt of the counter 8b is accepted. In addition, the time measurement result is initialized (content “0” is set), and new time measurement is started. That is, the time required to discharge the capacity corresponding to 10% of the compensation capacity is measured and written in the FIFO 10.

The FIFO 10 has four timing results (TUS0 to TUS0).
3) is provided with four storage areas for storing the CPU 11
Time measurement result T _SUM, which is the total of TUS 0 to 3
Is output. Further, the counter 8b outputs a value obtained by cutting off the lowest one digit of the value stored as the counting result (value of the upper three digits) to the CPU 11 as the counting result C _SUM . CPU1
1 monitors the on-off of the shaving switch 3 and the charging switch 4 recognizes the charge and discharge state of the battery 1 based on the state of each switch, timing result T _{SU M} and the count result C
It is a circuit that _executes a calculation based on _SUM .

The CPU 11 has an average time calculating means 11
a, a total time calculating means 11b, and a remaining use time calculating means 11c are provided. Average time calculation means 11a
Is the average time (T
_AVE ) is a means of calculating. Specifically, the following formula (Formula 1), average time (T _AVE ) = T _SUM / 4 · 60 [minutes], is calculated.

The total time calculating means 11b calculates the average time T _AVE.
It is a means for performing a calculation for calculating the capacity of the battery 1 at the completion of charging, that is, the total time required for discharging the compensation capacity, based on Specifically, the following equation (Equation 2), total time (T _FUL ) = 10 · T _AVE = T _SUM / 24
[Minutes], is calculated. In this case, since the average time T _AVE indicates the time required to discharge 10% of the compensation capacity, the time required to discharge all of the compensation capacity, that is, 100% is the average time T _{A VE} . It can be calculated by multiplying by "10". Here, this numerical value is called a constant.

The remaining usage time calculating means 11c refers to the counting result C _SUM of the counter 8b and the total time T _FUL, and refers to the battery 1
Is a means for performing a calculation for calculating the remaining usage time of the battery 1, that is, the remaining usage time at which the motor 2 can be driven based on the current capacity of the battery 1. Specifically, the following equation (Equation 3), remaining usage time (T _REM ) = T _FUL · (C _SUM / 100)
[Minutes], is calculated.

(C _SUM / 100) in the equation 3 is a proportional value showing the ratio of the counting result (C _SUM ) to the compensation capacity (100%).

The remaining usage time calculating means 11c outputs the counting result C _SUM to the LCD drive circuit 12 as the remaining capacity C _REM , and further outputs the remaining usage time T _REM to the LCD drive circuit 13. The time calculated by each means is stored in a storage means such as an internal register (not shown) provided in the CPU 11, and referred to as necessary.

The LCD drive circuits 12 and 13 have a CPU 11
The remaining capacity C _REM and remaining usage time T _REM output by
The capacity display portion 14a and the time display portion 14 of the CD panel 14
It is a circuit for performing control to selectively energize the display electrodes (display segment or the like) on the LCD panel 14 for displaying on b.

The capacitance display portion 14a of the LCD panel 14 is
It is composed of a plurality of display segments forming a bar graph showing the remaining capacity of the battery 1. Similarly, the time display unit 14b is composed of a plurality of display segments that form a numerical value indicating the remaining usage time.

When the battery 1 is charged for the first time in the apparatus having the above configuration, the CPU 11 causes the FIFO 10
Write 252 seconds, for example, in all three areas. On the other hand, the counting result C _SUM indicated by the counter 8b is the counting result of the pulses output by the V / F converter 7 based on the charging current,
Indicates the content "1000".

When the shaving switch 3 is turned on from this state and the driving of the motor 2 is started, the absolute value circuit 6 causes the voltage corresponding to the driving current (discharge current of the battery 1) and "-".
A polarity signal indicating is output. The V / F converter 7 outputs a pulse having a frequency proportional to the voltage, and outputs it to the counter 8b. When the polarity signal indicates "-", the counter 8b subtracts the content of the counter 8b in accordance with the number of input pulses. On the other hand, the timer 9 measures the time when the shaving switch 3 is on.

The counter 8b outputs an interrupt signal to the FIFO 10 and the timer 9 when counting the number of pulses corresponding to 10% of the compensation capacity. FIFO1 that accepted the interrupt
At 0, the output of timer 9 is written as TUS0. As a result, the timing result T _SUM, which is the total value of the new timing results TUS0 to 3, is output to the CPU 11. When the timer 9 receives the interrupt signal, the timer 9 outputs the time measurement result to the FIFO.
After outputting to 10, the time measurement result is initialized (the content is set to "0"), and new time measurement is started.

Every time an interrupt signal is output, in other words, a new time measurement result is written in the FIFO 10, C
The average time calculating means 11a of the PU 11 calculates the average time T _AVE , and the total time calculating means 11b calculates the total time T _FUL . The average time T _AVE and the total time T _FUL are calculated every time 10% of the capacity is discharged with respect to the compensation capacity.

On the other hand, the remaining usage time calculating means 11c performs a calculation for calculating the remaining usage time T _REM , for example, every 10 seconds while the shaving switch 3 is on. CPU
11 indicates that each time the new remaining usage time T _REM is calculated,
The LCD panel 14 is driven via the LCD drive circuits 12 and 13, and the remaining capacity C _REM is displayed on the capacity display section 14a and the remaining usage time T _REM is displayed on the time display section 14b. The remaining capacity C _REM and the remaining usage time T _REM are temporarily stored in an internal register or the like (not shown) of the CPU 11. Then, when the remaining usage time T _REM is newly calculated, it is compared with the temporarily stored remaining usage time T _REM . If the value of the new remaining time T _REM is large, the new remaining usage time T _REM is discarded without performing the temporary storage, that is, the display content of the time display unit 14b is not updated.

Now, referring to FIG. 2, a case where the battery 1 is discharged for the first time (first discharge) and a case where the battery 1 is discharged for the second time and thereafter (next discharge) will be described. FIG. 2 is an explanatory diagram relating to the remaining usage time display of the present invention. In the figure, the vertical axis represents the remaining usage time T _REM [minutes] displayed on the time display portion 14b of the LCD panel 14, and the horizontal axis represents the discharge time of the battery 1, that is, the shaving time [seconds].

When the battery 1 is discharged for the first time, that is, immediately after the first charging, and before the shaving switch 3 is turned on, the time measurement result of the timer 9 indicates "0", and the time measurement results TUS0 to 3 of the FIFO 10 are: All show 252 seconds. That is,
Calculation result of average time calculation unit 11a (average time T _AVE )
Indicates 4.2 minutes, and the calculation result (total time T _FUL ) of the total time calculating means 11b indicates 42 minutes. At this time, LCD
The capacity display portion 14a of the panel 14 shows 100% capacity,
The time display portion 14b displays the remaining usage time (MINUTES LEFT) 4
Display 2 minutes. This display shows that battery 1 is fully charged,
This means that the motor 2 can be driven for 42 minutes.

After that, when the shaving switch 3 is turned on and the first discharge is started, each time the counter 8b counts the capacity corresponding to 10% of the compensation capacity of the battery 1, the FIFO1
The stored content of 0 is updated to the content that actually reflects the driving result of the motor 2, and the average time T _AVE and the total time T _FUL are updated. When the counter 8b counts the capacity corresponding to 40% of the compensation capacity, the contents of the FIFO 10 are all based on the actual measurement data.

Generally, in the battery 1, there is a period when the discharge current is not stable in the discharge performed after the first charge is completed. In other words, the discharge current stabilizes as the discharge progresses. Therefore, the counter 8b has 10% to 10% of the compensation capacity.
The time measurement result written in the FIFO 10 when counting the capacity corresponding to 40% is low in reliability as a parameter for obtaining the total time T _FUL . After that, the counter 8b counts the capacity corresponding to 50% of the compensation capacity, and from the time when the time measurement result corresponding to the capacity of 20% to 50% of the compensation capacity is written in the FIFO 10, an almost accurate total time T _FUL is obtained. It has been confirmed experimentally that it can be calculated.

In the case of the figure, after the capacity corresponding to 50% of the compensation capacity is counted, the value of the time measurement result (about 348 seconds) written in the FIFO 10 becomes stable, so that the remaining usage time T _REM decreases in a substantially linear manner. To do.

When the remaining usage time T _REM reaches 0 and charging is started, that is, when the shaving switch 3 is turned off and the charging switch 4 is turned on by the control of the charging circuit 5, the CPU 11 causes the counter 8b to operate. The counting result of is monitored.
The absolute value circuit 6 outputs to the V / F converter 7 a voltage value corresponding to the charging current flowing in the direction opposite to that at the time of discharging the battery 1, and at the same time, outputs a polarity signal having a positive content to the counter 8b. .

When the counter 8b receives a positive polarity signal, the counter 8b performs counting for integrating the number of pulses output from the V / F converter 7. The CPU 11 uses the counter 8
The counting result of b is monitored, the LCD drive circuit 12 is driven based on the monitoring result, and display control of the capacitance display unit 14a is performed.
For example, every time the counter 8b counts the number of pulses corresponding to 20% of the compensation capacity, the CPU 11 causes the capacity display unit 14 to
Control is performed to turn on one segment of the bar graph of a.

Therefore, when the counter 8b counts the number of pulses corresponding to the compensation capacitance, all the segments of the capacitance display section 14a are turned on. When the CPU 11 detects the stop of charging, it drives the LCD drive circuit 13 to
Immediately before the start of charging, that is, when the capacity display unit 14a and the time display unit 14b both show 0, the total time T _FUL , which is the calculation result of the total time calculation means 11b, is displayed on the time display unit 14b. In the embodiment, the time display section 14b displays "58".
Minutes ”will be displayed.

Thereafter, using the value stored in the FIFO 10 immediately before the charging, that is, the timing result written when the stable discharging current flows from the battery 1, the average time T _AVE associated with the discharging of the battery 1, The total time T _FUL and the remaining usage time T _REM are calculated. That is, regarding the discharge (next discharge) performed after the second and subsequent charging is completed, the display content of the time display portion 14b changes substantially linearly from 58 minutes to 0 minutes. This is the absolute time (5
8 minutes) and the time when the display of the time display unit 14b changes from 58 minutes to 0 minutes are almost the same.

As described above, according to the present invention, the total time T _FUL for consuming the capacity (compensation capacity) of the battery 1 at the completion of charging is calculated based on the magnitude of the discharge current of the battery 1. Therefore, it is possible to display the total time T _FUL in consideration of the variation of the discharge current and the usage _pattern of the usage _pattern . Further, by accurately calculating the total time T _FUL , the change in the remaining usage time T _{REM that} decreases with the discharge of the battery 1 can be made to approximately match the absolute time. That is, the display content of the remaining usage time T _{REM and} the time actually required to discharge the battery 1 can be made to substantially coincide with each other.

The present invention is not limited to the above embodiments. In the embodiment, writing to the FIFO 10 is performed every time 10% of the compensation capacity is discharged, but a shorter cycle, for example, 5%.
Every time, or even longer cycle, eg 20%
You may change it every time you discharge. For every 5% discharge, the constant used by the remaining usage time calculation unit 11c is "20", and for every 20% discharge, the constant is "5". Also, the time measurement result written in the FIFO 10 is
The data may be written in the FIFO 10 after being taken in the CPU 11, weighted according to the value of the time measurement result. Specifically, when the value of the counting result is larger than the maximum value prepared in advance, this maximum value is used as the counting result in the FIFO1.
Similarly, if the value of the counting result is smaller than the minimum value prepared in advance, this minimum value is used as the counting result in FI.
Write to FO10. By limiting the value of the counting result in this way, it is possible to eliminate the influence of large fluctuations in the discharge current. Further, in addition to the shaving device, it can be applied to any device as long as it needs to calculate the dischargeable time based on the capacity charged in the battery.

[0041]

According to the device for calculating the remaining usage time of the battery of the present invention, the fluctuation of the discharge current of the battery which differs depending on the usage pattern of the battery is detected, and the compensation capacity of the battery affected by the fluctuation is discharged. Since the total time, which is the time required for, is calculated, it is possible to accurately calculate the total time that differs for each usage pattern. Also, by accurately calculating the total capacity, the remaining usage time can be easily and accurately calculated based on the result of integrating the discharge capacities of the batteries, and the user needs to be charged. It is possible to recognize the dischargeable time until the discharge.

[Brief description of drawings]

1 is a block diagram of an apparatus of the present invention.

FIG. 2 is an explanatory diagram relating to a remaining usage time display of the present invention.

[Explanation of symbols]

 1 Battery 2 Motor 6 Absolute Value Circuit 7 V / F Converter 8a Frequency Divider 8b Counter 9 Timer 10 FIFO 11 CPU 11a Average Time Calculation Means 11b Total Time Calculation Means 11c Remaining Use Time Calculation Means 14 LCD Panel

Claims (4)

[Claims] 1. A battery for which a compensation capacity to be regarded as the capacity at the time of completion of charging is set, a timer for measuring the usage time of the battery after the charging is stopped, and an integrating means for integrating the discharge capacity of the battery during use. A storage unit that stores a plurality of the use times measured by the time measuring unit each time the integration unit completes the integration of the reference capacity that is a part of the compensation capacity; and a plurality of storage units stored in the storage unit. And an average time calculating means for calculating an average value of the usage time, and a total time calculation for calculating a total time for the compensation capacity by multiplying the average value by a constant that is a multiplication factor for matching the reference capacity with the compensation capacity. Remaining usage of the battery, characterized by comprising: means and a remaining usage time calculating means for calculating a remaining usage time by multiplying the proportional time indicating the ratio of the compensation capacity and the discharge capacity by the total time. Time A device to calculate. 2. A conversion that detects the absolute value of the voltage generated in the resistance based on the resistance inserted in series with the battery and the current flowing through the resistance and outputs a pulse of a frequency corresponding to the voltage. The device for calculating the remaining usage time of the battery according to claim 1, wherein the integration of the discharge capacity by the integration unit is realized by counting the pulses. 3. The device for calculating the remaining usage time of a battery according to claim 1, further comprising a time display unit for displaying the remaining usage time. 4. The device for calculating the remaining usage time of a battery according to claim 1, wherein the accumulating unit integrates the charging capacity of the battery during charging.