JP2003151645A - Battery residual power detecting method and electric apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect battery residual power for operating electric apparatus. SOLUTION: According to a working condition of a battery, an initial value set to a battery residual power counter is measured. After the start of the use of the battery, battery residual power counter is subtracted at regular time intervals. A count value of the battery residual power counter is linearly decreased according to the elapse of the time, so that the battery residual power is clearly represented. If a voltage value is detected, although a required charging level may be determined, the battery residual power may not properly represented because the voltage abruptly drops right before charging is required. For a secondary battery, a initial value and a subtraction value can be corrected based on an actual result of previous use, and the life can be determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a remaining battery level in an electric device that operates using a battery as a power source and the electric device.

[0002]

2. Description of the Related Art Conventionally, a battery has been widely used as a power source for small and light electric devices which place importance on portability. As the battery, generally, a primary battery such as a dry battery that can be used only once and a secondary battery that can be charged and used repeatedly are used properly. Since a standard type dry battery, which is a typical primary battery, has a secondary battery of the same type, it can be selectively used in the same electric device. The primary battery needs to be replaced when the electric capacity is exhausted.
The secondary battery needs to be charged when the remaining charge is exhausted. For example, a secondary battery is used as a power source for mobile terminals such as a laptop computer and a mobile phone, and a battery remaining amount is displayed as a guide for the charging time. The secondary battery can be charged by a method in which the electric device itself that uses the secondary battery has a charging function, or a method in which the secondary battery is taken out from the electric device and then charged by the charging device. .

FIG. 9 shows a conventional way of thinking about displaying the remaining battery level. Generally, a battery has a discharge characteristic as shown by a solid line in the figure. Since the battery voltage decreases in accordance with the remaining amount, it is possible to know the replacement time of the primary battery and the charging time of the secondary battery by monitoring the battery voltage. However, due to the characteristics of the battery, the amount of decrease in the battery voltage is small while the remaining amount is large, and the battery voltage sharply drops after the remaining amount is small. Therefore, even if the battery voltage is monitored and the necessity of charging is displayed according to the voltage classification, for example, “blue”, “yellow”, and “red”, when considering on an operating time basis, “yellow” and “ The "red" time is short and the battery level indicator is often useless.

FIG. 10 shows a CR2 as an example of a primary battery.
The discharge characteristics of a coin-type lithium battery marketed as Type 032 are shown. Since a lithium battery has little self-discharge, it can be used for a long time if used with a minute discharge current. FIG. 10A shows the discharge characteristic at 20 ° C., the battery voltage is about 3 V, and it can be used for 600 hours or more with a load of 12 kΩ, that is, a discharge current of about 0.25 mA. The lithium battery having such characteristics has a condition that it can be permanently used in practical use. Under such conditions, once set, there is no need to charge or replace, and the power supply is simplified. For example, a CM that consumes less power is used for the timekeeping function of a personal computer and for backup such as saving set values.
It is often used in combination with a timer or memory formed by an OS type semiconductor integrated circuit. However, as shown in FIG. 10B, the usable time also changes depending on the temperature.

FIG. 11 shows a PR as another example of the primary battery.
The discharge characteristics of a mercury battery commercially available as Type 44 are shown below. In the mercury battery, compared to the lithium battery shown in FIG.
The change in the battery voltage in the middle of the discharge characteristic is small, and the battery voltage drops drastically after the remaining amount decreases.

FIG. 12 shows the charge / discharge characteristics of a sealed nickel-cadmium battery as an example of a secondary battery. 12
12A shows the charge characteristic, and FIG. 12B shows the discharge characteristic. The rated capacity C is 20 ° C as shown in Fig. 12 (b).
Is the product of the current value and the time when the final voltage of 1.1 V is reached in 1 hour by discharging. FIG. 12A shows 0.1
C, that is, the change in battery voltage when continuously charged at 1/10 of the current value reaching the final voltage by discharging for 1 hour. It is said that 150% of the standard charging should be performed as a standard. Fully charged state is confirmed by detecting that the specified battery voltage value has been reached, the battery voltage value has reached its maximum value, and that the change in battery voltage value has reached its maximum value and then dropped slightly over time. be able to. In the detection based on the battery voltage value, it is necessary to consider the temperature.

In Japanese Patent Laid-Open No. 57-200874, after the capacity C of the battery is initialized, the remaining amount that can be used for the discharge current i is calculated, and the remaining amount is divided by the discharge current i. A prior art is disclosed in which the remaining time is displayed every moment and the ambient temperature is also measured and reflected. JP-A 1-214478
Japanese Patent Publication No. 2 discloses a prior art in which the remaining capacity of a battery is displayed as the remaining number of times and the remaining time based on the measured values of the current usage amount and usage time per usage. In JP-A-6-258410, the remaining amount of the secondary battery is displayed according to the discharge current, and when it is determined that the battery voltage has reached the discharge end voltage determined according to the discharge current, Prior art is disclosed in which the remaining amount of the secondary battery is cleared to prevent the accumulation of display errors. Japanese Unexamined Patent Publication No. 10-207582 discloses an electronic device that may have different usage contents, such as an information processing device such as a personal computer used by a plurality of people, and has a database of the usage results for each usage content. The prior art is disclosed in which the time display also reflects the consumption according to the usage content. Japanese Patent Laid-Open No. 11-2367
No. 8 discloses that the battery voltage of a rechargeable battery does not necessarily correspond to a change in capacity, and in view of the fact that the battery voltage drops sharply after the remaining amount decreases, the usage time of the rechargeable battery is measured. Prior art for checking the remaining amount is disclosed.
Japanese Unexamined Patent Publication No. 11-289677 discloses a prior art in which the remaining amount is read from a battery and the remaining usage time is predicted from the latest consumption rate, but it is unknown how to read the remaining amount. .

In Japanese Patent Laid-Open No. 6-140080, the remaining amount of the secondary battery is calculated on the basis of the accumulated discharge time from the fully charged state, and even if the remaining amount should be more than a predetermined value, A prior art is disclosed that informs the user that the secondary battery has reached the end of its life and the time for battery replacement has come, when a reduced voltage state determined based on actual measurement of the voltage between terminals is detected. Japanese Unexamined Patent Publication No. 11-2670 discloses a system in which a plurality of secondary batteries are alternately switched to be charged when power is supplied from a DC power supply and discharged when power is cut off to retain the memory of a storage means. A prior art is disclosed in which the battery voltage of a secondary battery is monitored to store the capacity, and the life is predicted and displayed based on the aging change of the stored capacity.

[0009]

As shown in FIG. 9, it is more useful to estimate the remaining amount of the battery based on the usage time than to detect it based on the battery voltage. Such detection of the remaining amount is often performed on the secondary battery as in the above-described prior arts. However, as shown in FIG. 12, in the secondary battery, although the charge and discharge can be repeated, the capacity decreases with the repetition. When the capacity becomes 1/2 of the initial capacity, it is determined that the life has reached the end.
It is said that the sealed nickel-cadmium battery can be used for 500 cycles or more at a depth of discharge of 100% if it is charged at 0.1 C and 150% when discharged at room temperature of 1 ° C. At a depth of discharge of 70%, the cycle is 1000 cycles or more. As described above, although the life varies depending on the discharge condition and the operating temperature, the capacity in the fully charged state should gradually decrease even in the charging / discharging cycle in the middle of halving. In each of the above-mentioned prior arts, when predicting the battery capacity, the initial value is made constant, so there is a risk that the estimation accuracy of the remaining amount will deteriorate.

Even when the primary battery is used, the battery for replacement can be prepared in good timing if the time when the battery needs to be replaced can be accurately displayed. In particular, since the backup battery is not normally assumed to be replaced, it is necessary to appropriately notify when the replacement is necessary.

An object of the present invention is to provide a battery remaining amount detecting method and an electric device capable of accurately detecting the remaining amount of a battery for operating an electric device.

[0012]

SUMMARY OF THE INVENTION The present invention is a method for detecting the remaining amount of a battery in an electric device using a battery as a power source,
At the start of use of the battery, an initial value based on the usage condition of the battery is set in the battery remaining amount counter, and while the battery is in use, the battery remaining amount counter is subtracted at predetermined intervals to determine the battery remaining amount. It is a battery remaining amount detection method characterized by detecting the battery remaining amount from a remaining amount value indicated by a counter.

According to the present invention, in an electric device using a battery as a power source, an initial value based on the usage condition of the battery is set in the battery remaining amount counter. The initial value to be set can be obtained, for example, by correcting the capacity of the battery obtained from a test or experiment in consideration of the characteristics of the battery itself, the power consumption of the electric device, and the like. By setting an initial value that matches the usage condition of the battery in the electric device to the battery remaining amount counter, the battery remaining amount counter is decremented at regular intervals during use of the battery, and the battery remaining amount counter indicates The remaining battery level can be accurately detected from the remaining amount value.

Further, in the present invention, the battery is a secondary battery, charging and discharging are repeated, and it is determined whether charging is required based on the charge / discharge characteristics of the secondary battery. Is characterized in that the correction is made based on the subtracted amount to the battery remaining amount counter from the fully charged state to the detection of the required charging in the preceding use.

According to the present invention, in the electric device using the secondary battery as a power source, when the battery is repeatedly charged and discharged, the battery remaining amount counter from the full charge state to the charge required detection in the preceding use is detected. Since the initial value set in the battery level counter is corrected based on the subtracted amount, the initial value is corrected by reflecting the change in the battery capacity due to repeated charging / discharging, and the battery level indicated by the battery level counter The accuracy can be increased. As the remaining amount value indicated by the battery remaining amount counter, it is possible to indicate the remaining amount and the usable number of times.

In the present invention, the elapsed time from the fully charged state to the detection of the required charging is measured and stored, and when the required charging of the secondary battery is detected, the measured time from the fully charged state, It is characterized in that the stored initial measurement time is compared and the initial value is not corrected when the time difference increases or decreases beyond a predetermined range.

According to the present invention, when the measured time from the fully charged state of the secondary battery to the detection of the required charging is largely different from the measured time during the previous use, the operating condition of the electric equipment is used. Can be very different. Even if a new rechargeable battery is fully charged and started to be used, the usage conditions of electrical equipment may be different.Therefore, even if the initial value is corrected, the detection accuracy of the remaining amount cannot be improved. I can't
On the contrary, the accuracy may be deteriorated. By correcting the initial value only when the use condition is stable, it is possible to improve the remaining amount detection accuracy when the electric device is used stably.

Further, the present invention is characterized in that the battery remaining amount counter is set as the initial value with a measurement time from the full-charged state during the preceding use to the detection of the required charging.

According to the present invention, the battery remaining amount counter sets the measurement time from the fully charged state to the charge required detection in the preceding use, as an initial value, so that the battery remaining amount can be represented by time. . The actual measurement time of the previous use is set in the battery remaining amount counter as an initial value, and the actual capacity of the battery can be accurately reflected.

In the present invention, the initial value is compared with the measurement time from the full-charged state to the detection of charge required, and the subtraction value is determined according to whether the measurement time is larger or smaller than the initial value. Is updated so as to be smaller or larger, respectively.

According to the present invention, when the measured time is larger than the initial value, the battery remaining amount counter is corrected so that the subtracted value for subtracting at regular intervals becomes small, so that the next battery is used, The remaining amount value of the battery remaining amount counter at the time of charge required detection becomes large, and the accuracy can be improved by performing correction so as to approach the measurement time. When the measured time is smaller than the initial value, the remaining battery level counter is subtracted at fixed time intervals so that the subtracted value is increased
In the next use of the battery, the remaining amount value of the battery remaining amount counter at the time of charge required detection becomes small, and the correction can be performed so as to approach the measurement time, and the accuracy can be improved.

Furthermore, the present invention is an electric device using a battery as a power source, wherein a battery remaining amount counter for outputting an estimated value of the remaining amount of the battery and a battery remaining amount counter are used, and any one of the above is described. An electric device comprising: a remaining amount detecting means for detecting a remaining amount of the battery by a remaining battery amount detecting method; and a remaining amount displaying means for displaying a detection result of the remaining amount detecting means.

According to the present invention, the remaining amount of the battery can be detected from the battery remaining amount counter by the remaining amount detecting means,
Since the remaining amount is displayed on the remaining amount display means, it is possible to perform the display based on the highly accurate detection of the remaining amount of the battery, and appropriately manage the time of battery replacement and charging.

Further, the present invention relates to an electric device using a secondary battery as a power source, which uses a battery remaining amount counter for outputting an estimated value of the remaining amount of the battery and a battery remaining amount counter, and is used in any one of the above. A remaining amount detecting means for detecting the remaining amount of the secondary battery by the remaining battery amount detecting method described above, a remaining amount displaying means for displaying the detection result of the remaining amount detecting means, and a judgment about the life of the secondary battery. An electrical device comprising: a life determining means; and a life displaying means for displaying the determination result when the life determining means determines that the secondary battery has reached the end of life.

According to the present invention, it is properly judged whether or not the secondary battery to be used while repeating charging and discharging has reached the end of its life, and when it is judged that it has reached the end of its life, the judgment result is given. Can be displayed. Since the display is displayed when the secondary battery has reached the end of its life, it is possible to prompt replacement of the deteriorated secondary battery at an appropriate timing without continuing use.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the basic idea of remaining battery level detection according to the present invention. As shown in FIG.
First, an initial value for measuring the remaining battery level using a battery remaining counter is measured. The measurement of the initial value can be performed by experiments and tests. If the battery is a secondary battery, change from the fully charged state to the required charge state where the remaining amount runs out
For example, the initial value can be obtained by the product of the current and the time from the battery voltage to the time of detection. If the discharge current is constant, the battery capacity corresponds to time. When the initial value is set in the battery remaining amount counter at the start of the battery and the battery remaining amount counter is subtracted with a constant time gradient as shown in FIG. 1B, the count value of the battery remaining counter becomes Corresponding to the remaining battery level, "blue", "yellow", "red" on the battery level indicator
Classification such as can be appropriately performed. In the present embodiment, in a battery-powered electric device, when a specific event occurs, the subtracted value of the battery remaining amount counter is changed. For example, when an event of turning on the backlight of the display device occurs, the discharge current of the battery increases, and the subtracted value of the battery remaining amount counter also increases.

FIG. 2 shows a schematic electrical configuration of an electric device 1 having a function of detecting the remaining battery level according to the concept of FIG. The electric device 1 operates by using the battery 2 as a power source,
The remaining amount of the battery 2 is detected based on the battery remaining amount counter 3. The count value of the battery level counter 3 is subtracted at regular time intervals measured by the timer 4. The remaining amount of the battery 2 is detected by the remaining amount detecting means based on the count value of the battery remaining amount counter 3. If the load 7 of the battery 2 is constant, the remaining amount detecting means 6 subtracts the count value of the battery remaining amount counter 3 by a constant subtraction value. When an event in which the electric power consumption varies in the electric device 1 occurs, the subtraction value is changed. The battery voltage at the terminal of the battery 2 is converted into a digital value by an analog / digital conversion circuit (hereinafter abbreviated as “A / D”) 8 and input to the remaining amount detecting means 6.
The remaining amount detecting means 6 is also given an output from a temperature sensor 9 for detecting the ambient temperature and the like.

FIG. 3 shows a procedure for making various settings and shipping as a product when the electric device 1 of FIG. 2 is manufactured. The procedure is started from step a0, and in step a1, the battery 2 is put into a test state and a test mode preset in the remaining amount detecting means 6 is started. Instead of the remaining amount detecting means 6, a test mode may be provided on the test device side. When an event occurs in step a2,
The current is measured in step a3, and the subtracted value for each event is stored in step a4. The remaining amount detecting means 6 is provided with a non-volatile memory such as a flash ROM for storing data such as a subtraction value. Step a5
To end the procedure.

If the battery 2 used in step a1 is a primary battery, an unused battery is used. If it is a mass-produced product, the selected sample will be tested, and the test results will be reflected in products other than the sample. The battery 2 of the tested sample is replaced with an unused item when shipped as a product. If the battery 2 is a secondary battery, it is returned to a fully charged state and shipped as a product. The initial value as shown in FIG. 1A can also be measured by this procedure.

FIG. 4 shows a schematic processing procedure for detecting the remaining amount of the battery 2 using the battery remaining amount counter 3. At step b0, the interruption by the timer 4 at regular intervals is given to the remaining amount detecting means 5. This fixed period of time is sufficiently shorter than the period of use of the battery 2. At step b1, the subtracted value of the battery remaining amount counter 3 is corrected according to a preset condition. Step b
In 2, the battery remaining amount counter 3 using the corrected subtracted value
The count value of 1 is subtracted, and the process returns to the process before the interrupt occurs in step b3.

FIG. 5 shows a processing procedure for remaining amount detection performed by the remaining amount detecting means 6. The remaining amount detecting means 6 is
It is realized by a microcomputer or the like and performs processing and control for remaining amount detection according to a preset program. The procedure is started from step c0, and the temperature is detected by the temperature sensor 9 in step c1. In step c2, the battery level counter 3
Correct the subtraction value that is subtracted at a constant time interval. At step c3, it is determined whether or not an event occurs in the electric device 1 with a change in the usage state of the current from the battery 2. If an event has occurred, the subtraction value is corrected according to the event in step c4. When it is determined in step c3 that no event has occurred, or when the correction is completed in step c4, the entire procedure is completed in step c5.

In this embodiment, at the start of use of the battery 2,
An initial value based on the usage condition of the battery 2 is set in the battery remaining amount counter 3, and the battery remaining amount counter 3 is subtracted at predetermined intervals during use of the battery 2 to obtain the remaining amount indicated by the battery remaining amount counter 3. The battery level is detected from the value. As described above, the initial value set in the battery remaining amount counter 3 is corrected by taking into consideration the characteristics of the battery 2 itself, the power consumption of the electric device 1, etc., for example, the capacity of the battery 2 obtained from a test or experiment. It can be obtained. The battery 2 in the electric device 1
By setting an initial value that matches the usage condition of, the battery remaining amount counter 3 is subtracted every predetermined time during use of the battery 2, and the battery remaining amount indicated by the battery remaining amount counter 3 is accurately measured. The amount can be detected.

When the battery 2 is a secondary battery, charging and discharging are repeated, and it is determined whether charging is required based on the charge / discharge characteristics of the secondary battery. The initial value set in the battery remaining amount counter 3 is corrected based on the subtracted amount of 6 to the battery remaining amount counter from the fully charged state in the preceding use to the detection of charge required. As a result, the initial value can be corrected by reflecting the change in the capacity of the battery 2 due to repeated charging / discharging, and the accuracy of the remaining amount value indicated by the battery remaining amount counter 3 can be increased. As the remaining amount value indicated by the battery remaining amount counter 3, it is possible to indicate the remaining amount and the usable number of times.

Further, the elapsed time from the fully charged state of the battery 2 to the detection of the required charging is measured and stored in a non-volatile memory or the like, and when the required charging is detected, the measured time from the fully charged state is stored. When the time difference is increasing or decreasing beyond a predetermined range, the initial value is not corrected. If the measured time from the fully charged state of the secondary battery to the time when the required charging is detected is largely different from the measured time during the previous use, it is considered that the usage conditions of the electric device 1 are significantly different. To be Even if the rechargeable battery is fully charged and started to be used, the usage conditions of the electric device 1 may be different. Therefore, even if the initial value is corrected, the remaining amount detection accuracy should be improved. However, the accuracy may be deteriorated. By correcting the initial value only when the use condition is stable, it is possible to improve the remaining amount detection accuracy when the electric device 1 is used stably.

Further, the battery remaining amount counter 3 can be set as an initial value with a measurement time from the full-charged state in the preceding use to the detection of charge required. The remaining amount of the battery 2 can be represented by time by setting the measurement time from the fully charged state to the detection of the required charging in use prior to the battery remaining amount counter 3 as an initial value. The actual measurement time of the previous use is set in the battery remaining amount counter 3 as an initial value, and the actual capacity of the battery 2 can be accurately reflected.

FIG. 6 shows a schematic electrical configuration of an electric device 11 according to another embodiment of the present invention. The electric device 11 of the present embodiment operates by using the battery 12, which is a secondary battery, as a power source. The remaining amount of the battery 12 is determined by the remaining amount detection processing unit 15 including the battery remaining amount counter 13 and the timer 14.
The remaining amount detection processing unit 15 displays the remaining amount detection result on the display unit 16 as a remaining amount display unit. The power supplied by the battery 12 is used by the terminal main circuit 17. When the electric device 11 is a mobile phone, in the terminal main circuit 17, an event such as an incoming call, an internet connection, a vibration operation, or backlight lighting may occur. The battery voltage at the terminals of the battery 12 is converted to a digital value by the A / D 18. The ambient temperature of the battery 12 or the temperature of the direct battery 12 is converted into an electric signal by the temperature detection unit 19 and converted into a digital value by the A / D 18. A /
The digital value converted by D18 is input to the CPU 20 as the remaining amount detecting means.

The CPU 20 detects the remaining amount of the battery 12 according to a preset program in a procedure basically equivalent to the procedure shown in FIGS. In the present embodiment, the voltage detection unit 21 is provided to detect the battery voltage of the battery 12, and the current detection unit 22 is provided to detect the current supplied to the terminal main circuit 17. The current detection unit 22 can measure the voltage drop of the current detection resistor 23 and divide the measured voltage by the resistance value of the current detection resistor 23 to obtain the current. The detection outputs of the voltage detection unit 21 and the current detection unit 22 are converted into digital values by the A / D 18 and input to the CPU 20.

The operating state of the terminal main circuit 17 is input to the CPU 20 via an interface circuit for input (hereinafter abbreviated as "input I / F"). CPU20
Can control the switch 26 via the output unit 25 to short-circuit both ends of the current detection resistor 23. Electrical equipment 1
1 is in the normal use state, the switch 26 is closed, and the switch 2 is set in the test mode at the time of product shipment as shown in FIG.
Open 6 for current measurement. The measurement result in the test mode is stored in the non-volatile storage unit 27.

The discharge characteristic of the battery 12 changes according to the operating temperature, and the usable capacity also changes. For example, by decreasing the subtraction value at high temperature and increasing the subtraction value at low temperature and changing the subtraction value according to the temperature characteristics of the battery, it is possible to improve the accuracy of remaining amount detection. Since the discharge characteristic changes depending on the type of the battery 12, the subtraction value of the battery remaining amount counter 13 can be changed according to the temperature characteristic of the battery 12 to detect the remaining amount of the battery 12 with high accuracy even if the temperature changes. it can.

In the subtraction of the battery remaining amount counter 13, the subtraction value is changed in the operation of the electric device 11 according to the presence or absence of a preset event. In the operation of the electric device 11, a specific operation state is set as an event, for example, in a mobile phone, a connection to a communication line, a vibration operation, a backlight lighting, and the like are set, and the battery remaining amount is determined depending on the presence or absence of any of these. Since the subtracted value of the counter is changed, it is possible to accurately detect the remaining amount of the battery 12 by reflecting the power consumption at the event.

In the subtraction of the battery capacity counter 13, the battery 1
The subtraction value is changed according to the discharge current value from 2. Battery 1
Since the decrease amount of the remaining amount of 2 changes according to the discharge current value, the accuracy of the remaining amount can be increased by changing the subtraction value of the battery remaining amount counter 13 according to the discharge current value. .

FIG. 7 shows the procedure of the battery remaining amount detection and the detection result display operation in the embodiment of FIG. Step d0
The procedure is started from, and in step d1, it is determined whether or not the battery 12 is fully charged. If it is not fully charged, wait for it to be charged. When it is determined that the battery is in the fully charged state, loading is performed to set the initial value stored in the storage unit 27 in the battery remaining amount counter 13 in step d2. The display unit 16 displays the remaining amount of "blue". The use of the battery 12 is started from step d3, and the battery remaining amount counter 13 is decremented at regular intervals as in the embodiment of FIG. 2, while at step d4, the “blue” area shown in FIG. The yellow detection is performed to determine whether or not it is out of the range. When it is determined that the battery remains in the “blue” area, the process returns to step d3 and the battery level counter 13
Continue subtraction of. When it is determined in step d4 that yellow is detected, the process proceeds to step d5, and red detection is performed to determine whether or not it is within the "red" area shown in FIG. 1 (b). When it is determined that the area is not in the "red" area, the process proceeds to step d6, the remaining amount of "yellow" is displayed on the display unit 16 as a yellow display, and the procedure ends at step d7. If it is determined in step d5 that it is in the "red" area, the process moves to step d8.
The remaining amount of "red" is displayed on the display unit 16 as a red display, and the procedure ends at step d9.

FIG. 8 shows a procedure of battery life detection and detection result display operation performed in parallel with the remaining amount detection of FIG. 7 in the embodiment of FIG. Each step from step e0 to step e2 is equivalent to each step from step d0 to step d2 in FIG. At step e3, as shown in FIG.
The voltage counter set in the storage unit 27 is initialized to 0 at the start of use of the battery 12, and a voltage count for adding the subtracted value to the battery remaining amount counter 13 is performed at regular time intervals during use. In step e4, it is determined whether or not the battery voltage detected by the voltage detection unit 21 reaches the discharge end voltage based on the characteristics of the battery 12 and the battery needs to be charged. If it is determined that the battery does not need to be charged, step e
Continue counting the voltage at 3. When it is determined in step e4 that the battery needs to be charged, the battery remaining amount counter 13
The initial value to be set to is compared with the count value of the voltage counter. The count value of the voltage counter is equal to the cumulative value of the subtracted values by which the battery remaining amount counter 13 is subtracted from the fully charged state of the battery 12 to the detection of charge required.

At step e6, the subtraction value is corrected based on the comparison result at step e5. The subtracted value can directly use the time. When the subtracted value is time, it means that the initial value is compared with the measurement time from the fully charged state to the detection of charge required. The subtraction value is updated to be smaller or larger depending on whether the measurement time is larger or smaller than the period value. When the measured time is larger than the initial value, the battery remaining amount counter 13 is corrected so that the subtracted value that is subtracted at regular time intervals becomes small, so that the next battery 12 is used, the battery at the time of detection of charge required is detected. The remaining amount of the remaining amount counter 12 becomes large,
The accuracy can be improved by learning by performing correction so as to approach the measurement time. When the measured time is smaller than the initial value, the battery remaining amount counter 12 is corrected so that the subtracted value that is subtracted at regular intervals becomes large, so that the next battery 12 is used, the battery at the time of detection of charge required is detected. Remaining amount counter 1
The remaining amount value of 3 becomes small, and the accuracy can be improved by performing correction so as to approach the measurement time.

At step e7, the initial value is corrected by learning. As the correction of the initial value, the measured value of the voltage counter can be directly used as the correction value. However, when the difference between the initial value and the measured value of the voltage counter has increased or decreased by a certain value or more, it is considered that the operating state of the electric device 11 is significantly different. Since the error in the remaining amount detection may increase even in the next use, the correction is not performed.

In step e8, it is determined whether or not the measurement time from the fully charged state to the detection of required charging continuously decreases for a predetermined number of times or more and decreases by a predetermined value or more based on the data stored in the storage unit 27. Judge. When the capacity that can be used from the full-charged state to the detection of the required charge decreases significantly each time charging and discharging are repeated, it can be determined that the performance of the secondary battery has deteriorated and has reached the end of its life. When the secondary battery reaches the end of its useful life, the usable capacity will decrease even when it is fully charged, making it difficult to detect the remaining amount with high accuracy. .

Next, at step e9, it is judged whether or not the initial value set in the battery remaining amount counter 13 has reached a preset lower limit value. The initial value set in the battery remaining amount counter 13 is corrected by reflecting the measurement time from the full-charged state of the secondary battery in the preceding use to the detection of charge required. If the measurement time becomes shorter, the initial value will also decrease.
If the lower limit value is set in advance and the initial value reaches the lower limit value, it can be determined that the secondary battery has reached the end of its life.

Next, at step e10, it is judged whether or not the subtracted value of the battery remaining amount counter 13 has reached the preset upper limit value. The subtraction value subtracted from the battery remaining amount counter 13 at regular intervals during use of the battery 12 increases as the capacity of the battery 12 in the fully charged state decreases. Battery 12
Is increased, the subtraction value increases, and when the preset upper limit value is reached, it can be determined that the battery 12 has reached the end of its life.

When it is judged at step e8, step e9 or step e10 that the battery life has been reached, the battery life is displayed on the display unit 16 at step e11, and the procedure ends at step e12. The battery life display is performed in a blinking state, for example. Step e
When it is determined that the life has not reached the end of any of step 8, step e9 and step e10, the process returns to step e3. It should be noted that the life judgment of step e8, step e9, or step e10 may be only one or may be a combination of two. By making three determinations as in the present embodiment, it is possible to increase the possibility of detecting the battery life. While repeating charging and discharging, it is possible to properly judge whether the secondary battery to be used has reached the end of its life, and when it is judged that it has reached the end of its life, the judgment result can be displayed, so it has deteriorated. Do not continue to use the secondary battery,
It is possible to encourage replacement at an appropriate time.

[0050]

As described above, according to the present invention, in an electric device using a battery as a power source, an initial value based on the usage condition is set in the battery remaining amount counter, and the battery remaining amount counter is set during use of the battery. It is possible to detect the battery remaining amount with high accuracy from the remaining amount value indicated by the battery remaining amount counter by performing subtraction at predetermined constant intervals.

Further, according to the present invention, in the electric device using the secondary battery as a power source, the initial value set in the battery remaining amount counter is corrected based on the subtracted amount in the preceding use, so that charging and discharging are repeated. The accuracy of the remaining amount value indicated by the battery remaining amount counter can be improved by reflecting the change in the battery capacity.

Further, according to the present invention, the measurement time from the fully charged state of the secondary battery to the detection of the required charging has a large difference compared with the measurement time at the previous use, and the use condition of the electric equipment is If there is a large difference, the initial value is not corrected, and the initial value is corrected only when the usage conditions are stable, so the remaining amount detection accuracy when the electrical equipment is used stably Can be increased.

According to the present invention, the actual capacity of the battery can be accurately detected by setting the actual measurement time in use prior to the battery remaining amount counter as the initial value.

Further, according to the present invention, the pre-measurement time is compared with the initial value, and the subtraction value for subtracting the battery remaining amount counter at regular intervals is corrected according to the comparison result. The remaining amount value of the battery remaining amount counter at the time of detection of charge required can be corrected to correspond to the measurement time, and the accuracy can be improved.

Further, according to the present invention, the display based on the highly accurate detection of the remaining amount of the battery is performed from the battery remaining amount counter,
It is possible to properly manage the time of battery replacement and charging.

Further, according to the present invention, while repeatedly charging and discharging, it is properly judged whether or not the secondary battery to be used has reached the end of its life, and when the end of the life is reached, display is carried out. It is possible to encourage replacement at an appropriate time.

[Brief description of drawings]

FIG. 1 is a time chart showing the basic idea of the present invention.

FIG. 2 is a block diagram showing a schematic electrical configuration of an electric device 1 according to an embodiment of the present invention.

FIG. 3 is a flowchart showing an operation procedure of the electric device 1 of FIG.

FIG. 4 is a flowchart showing an operation procedure of the electric device 1 of FIG.

5 is a flowchart showing an operation procedure of the electric device 1 of FIG.

FIG. 6 is a block diagram showing a schematic electrical configuration of an electric device 11 according to another embodiment of the present invention.

FIG. 7 is a flowchart showing an operation procedure of the electric device 11 of FIG.

8 is a flowchart showing an operation procedure of the electric device 11 of FIG.

FIG. 9 is a time chart showing the conventional way of thinking of battery remaining amount detection.

FIG. 10 is a graph showing an example of characteristics of a primary battery.

FIG. 11 is a graph showing another example of the characteristics of the primary battery.

FIG. 12 is a graph showing an example of characteristics of a secondary battery.

[Explanation of symbols]

1,11 Electric equipment 2,12 batteries 3,13 Battery level counter 4,14 timer 5 Remaining amount detection means 6 Remaining amount display means 7 load 8,18 A / D 9 Temperature sensor 15 Remaining amount detection processing unit 16 Display section 17 Terminal main circuit 19 Temperature detector 20 CPU 21 Voltage detector 22 Current detector 27 Memory

Claims (7)

[Claims] 1. A method of detecting a remaining amount of a battery in an electric device using a battery as a power source, wherein an initial value based on a use condition of the battery is set in a battery remaining amount counter at the start of use of the battery, A battery remaining amount detecting method, wherein the battery remaining amount counter is subtracted every predetermined time during use of the battery, and the battery remaining amount is detected from the remaining amount value indicated by the battery remaining amount counter. 2. The battery is a secondary battery, charging and discharging are repeated, and it is determined whether charging is required based on charge / discharge characteristics of the secondary battery. 2. The battery remaining amount detecting method according to claim 1, wherein the correction is performed based on a subtracted amount to the battery remaining amount counter from the full-charged state to the detection of the required charging during use. 3. The elapsed time from the fully charged state to the detection of the required charging is measured and stored, and when the required charging of the secondary battery is detected, the measured time from the fully charged state is stored. The remaining battery level detection according to claim 2, wherein the initial value is not corrected when the time difference has increased or decreased over a predetermined range by comparing the measured time of the previous use. Method. 4. The battery remaining amount according to claim 3, wherein the battery remaining amount counter is set with a measurement time from the full-charged state during the preceding use to the detection of the charge required as the initial value. Quantity detection method. 5. The initial value is compared with the measurement time from the full-charged state to the detection of charge required, and the subtraction value is reduced depending on whether the measurement time is larger or smaller than the initial value. Alternatively, the battery remaining amount detection method according to claim 4, wherein the battery is updated to be larger. 6. An electric device that uses a battery as a power source, wherein a battery remaining amount counter that outputs an estimated value of the remaining amount of the battery and a battery remaining amount counter are used. An electric device comprising: a remaining amount detecting means for detecting the remaining amount of the battery by the remaining battery amount detecting method and a remaining amount displaying means for displaying a detection result of the remaining amount detecting means. 7. An electric device using a secondary battery as a power source, wherein a battery remaining amount counter for outputting an estimated value of the remaining amount of the battery and a battery remaining amount counter are used, and any one of claims 1 to 5 is used. A remaining amount detecting means for detecting the remaining amount of the secondary battery by the remaining battery amount detecting method described in, a remaining amount displaying means for displaying a detection result of the remaining amount detecting means, and a judgment about the life of the secondary battery. An electric device comprising: a life determining means to perform; and a life displaying means for displaying the determination result when the life determining means determines that the secondary battery has reached the end of life.