JP2000014033A - Charge control equipment and charge control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide charge control equipment of a secondary battery which can prevent deterioration of battery function caused by influence of electromagnetic waves during charge. SOLUTION: In a charge control equipment controlling charge of a secondary battery, electromagnetic wave monitoring means 1, 2 detecting the electric field level of electromagnetic waves incoming from the outside, and a control means 6 which switches over a switching part 4 on the basis of detected results of the electromagnetic waves by the electromagnetic wave monitoring means and controls a charging voltage of a constant voltage control circuit part 3 are installed. Thereby generation of overvoltage charge in a battery 7 which is to be caused by disturbance electromagnetic waves can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging control device and a charging control method for a device having a built-in secondary battery, and more particularly, to preventing a battery from being overcharged due to electromagnetic waves.

[0002]

2. Description of the Related Art A conventional telephone device having a built-in lithium ion secondary battery has a charging circuit for controlling charging of the secondary battery. The charging circuit unit includes a constant voltage or constant current control circuit that controls a voltage or current from a power supply to a constant value and supplies the lithium ion secondary battery, and a charge control circuit that monitors the battery voltage or current. When the charging control circuit detects a current indicating the end of charging (charging termination current), the charging control circuit stops the supply of charging power from the constant voltage or constant current control circuit.

However, when charging is performed in the presence of an interfering electromagnetic wave, a noise ripple occurs in the charging voltage depending on the electric field level of the interfering electromagnetic wave, and the battery is overvoltage-charged more than the allowable voltage deviation of the charging. May deteriorate.

When it is necessary to prevent the influence of such interfering electromagnetic waves, generally, the circuit portion is housed in a metal shield case as disclosed in Japanese Patent Application Laid-Open No. 7-170087. .

Further, in order to avoid electromagnetic interference, Japanese Patent Application Laid-Open
In -284100, a synchronization signal of a radio signal arriving at a wireless line is detected at a fixed time interval, a period during which the synchronization signal cannot be detected is counted up, and when the count value reaches a predetermined value, the radio wave is obstructed. A cordless telephone has been disclosed which identifies the user as an electromagnetic wave and alerts a user to move the telephone to a place where interference electromagnetic waves are low.

[0006]

However, if the charging device is housed in a metal case in order to eliminate the influence of the interfering electromagnetic waves, there is a problem that the size and weight of a telephone or the like incorporating the charging device are hindered. is there. In addition, the measure of detecting the presence or absence of an interfering electromagnetic wave and moving to a place where there is no interfering electromagnetic wave is practically impossible in the case of charging.

[0007] The present invention solves such conventional problems, and can prevent deterioration of battery performance due to the influence of electromagnetic waves during charging, and can reduce the size and weight of products. It is an object of the present invention to provide a charge control device for a secondary battery and a charge control method thereof, and to further provide a wireless telephone device to which the devices are applied.

[0008]

SUMMARY OF THE INVENTION Therefore, in a charging control device according to the present invention, an electromagnetic wave monitoring means for detecting an electric field level of an electromagnetic wave arriving from the outside, and a charging current or a charging current based on a detection result of the electromagnetic wave by the electromagnetic wave monitoring means. And control means for controlling the voltage.

Further, in the charging control method of the present invention, the electric field level of an electromagnetic wave arriving from the outside is detected, and when the electric field level exceeds a threshold value, the charging current or the charging voltage is suppressed, and the time until the charging is stopped. The charging time is controlled.

Further, in the wireless telephone device of the present invention, when transmission by the transmitter is started during charging of the secondary battery, the electric field strength of the power level transmitted from the transmitter is recognized,
Charging control means for controlling the charging current or the charging voltage based on the recognition result is provided.

Therefore, it is possible to prevent the secondary battery from being overvoltage-charged due to the electromagnetic wave during charging, and to prevent the performance of the battery from deteriorating. Further, since the metal shield of the charging circuit is not required, the size and weight of the device incorporating the secondary battery can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An invention according to claim 1 of the present invention is directed to a charge control device for controlling charging of a secondary battery,
An electromagnetic wave monitoring means for detecting an electric field level of an electromagnetic wave arriving from the outside, and a control means for controlling a charging current or a charging voltage based on a detection result of the electromagnetic wave by the electromagnetic wave monitoring means are provided. The occurrence of overvoltage charging can be prevented.

According to a second aspect of the present invention, the control means includes a comparing means for comparing the detected electric field level with a threshold value, and the charging current or the charging voltage is suppressed based on the comparison result of the comparing means. In addition, the charging time until the charging is stopped is controlled. Even if the completion of the charging cannot be detected, the charging is stopped after the charging time elapses, thereby preventing the battery from being overcharged. In addition, it is possible to suppress deterioration of battery performance and cycle life.

According to a third aspect of the present invention, the comparing means ranks the electric field level by comparing the electric field level with a plurality of thresholds, and the control means determines the charging time until the charging is stopped based on the rank. The length of the battery is set so that the charging time is short when the electric field level of the interfering electromagnetic wave is high, and the charging time is long when the electric field level of the interfering electromagnetic wave is low. Prevent
In addition, the charging rate up to the stop of charging can be increased as much as possible.

According to a fourth aspect of the present invention, the control means is provided with a counter for counting the number of times the charging current or the charging voltage is controlled based on the detection result of the electromagnetic wave monitoring means, and the counter is provided on the way to completion of the charging. When the value of 値 reaches a predetermined value, charging is stopped. In addition to limiting charging time, double protection means is used as protection means for avoiding entry into the charging dangerous area. Can be configured.

According to a fifth aspect of the present invention, the control means is provided with a timer for counting the time from the stop of charging, and after the timer measures a predetermined time, charging is restarted. The state where the charging capacity is not satisfied due to the stop can be eliminated by restarting the charging.

According to a sixth aspect of the present invention, in the charge control method for controlling charging of the secondary battery, an electric field level of an electromagnetic wave arriving from the outside is detected, and when the electric field level exceeds a threshold value, a charging current is detected. Or suppress the charging voltage, and
The charging time until the charging is stopped is controlled, so that overvoltage charging of the battery can be prevented, and performance degradation of the battery can be suppressed.

According to a seventh aspect of the present invention, the charging time until the charging is stopped is set based on the magnitude of the voltage level of the electromagnetic wave, and when the electric field level of the interfering electromagnetic wave is high, If the charging time is short and the electric field level of the interfering electromagnetic wave is low, the charging time is set to be long, so that overvoltage charging of the battery can be prevented, and the charging rate until the charging is stopped can be increased as much as possible.

According to the present invention, the number of times the charging current or the charging voltage is controlled based on the detection result of the electric field level of the electromagnetic wave is counted, and the number reaches a predetermined value halfway until the charging is completed. When charging is performed, charging is stopped, and entry into the dangerous charging area can be protected by double means in addition to limiting charging time.

According to a ninth aspect of the present invention, after the charging is stopped, the charging is restarted after a lapse of a predetermined time. The state in which the charging capacity is not satisfied due to the stop of the charging is determined by restarting the charging. Can be eliminated.

According to a tenth aspect of the present invention, in a wireless telephone device having a built-in secondary battery and a built-in transmitter for continuous transmission, transmission by the transmitter is started during charging of the secondary battery. At this time, a charging control means for recognizing the electric field intensity of the power level transmitted from the transmitter and controlling the charging current or the charging voltage based on the recognition result is provided. The situation where the secondary battery is overcharged can be prevented.

According to an eleventh aspect of the present invention, the charging control means is provided with a comparing means for comparing the recognized electric field strength with a threshold value, and the charging current or the charging voltage is suppressed based on the comparison result of the comparing means. In addition, the charging time until the charging is stopped is controlled, so that overvoltage charging of the battery can be prevented and deterioration of the performance of the battery can be suppressed.

According to a twelfth aspect of the present invention, the comparing means ranks the electric field strength of the power level by comparing the electric field strength with a plurality of thresholds, and the charging control means determines whether or not the charging is stopped based on the rank. The length of the charging time is set, the overvoltage charging of the battery can be prevented, and the charging rate until the charging is stopped can be increased as much as possible.

According to a thirteenth aspect of the present invention, the charging control means is provided with a timer for counting the time from the stop of charging.
After the timer measures a predetermined time, the charging is restarted, and the state in which the charging capacity is not satisfied due to the stop of the charging can be eliminated by restarting the charging.

According to a fourteenth aspect of the present invention, in a wireless telephone device having a built-in secondary battery and a built-in transmitter for performing transmission in the TDMA system, transmission by the transmitter is performed while the secondary battery is being charged. When started, stop charging during the time-divided transmission period based on the transmission control signal of the transmitter,
In the non-transmission period, charging control means for controlling charging is provided, and charging can be performed while avoiding the influence of electromagnetic waves during transmission.

According to a fifteenth aspect of the present invention, a lithium ion secondary battery is used as the secondary battery, and the performance and cycle life of the lithium ion secondary battery can be protected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) As shown in FIG. 1, a charge control device according to this embodiment includes a constant voltage control circuit section 3 for supplying a constant charge voltage to a lithium ion secondary battery 7;
A charge control circuit section 5 for monitoring the state of charge of the lithium ion secondary battery 7, a simple antenna 1 for receiving an externally disturbing electromagnetic wave, and a detection circuit section 2 for converting a signal received from the simple antenna 1 into a DC voltage. A main control unit (CPU) 6 that controls charging; and a switch unit 4 that switches the mode of charging control under the control of the CPU 6.

The CPU 6 also includes a comparator for comparing the electric field level detected by the detection circuit section 2 with a threshold value to determine the presence or absence of an interfering electromagnetic wave, an electromagnetic wave detection counter for counting the number of times the presence of the interfering electromagnetic wave is determined, A timer for measuring time.

In this charging control device, the simple antenna 1 receives an externally-disturbed electromagnetic wave, and the detection circuit 2 detects the level of the electric field. The CPU 6 compares the electric field level output from the detection circuit section 2 with a threshold value by a comparison calculator, and when the electric field level does not exceed the threshold value, the switch section 4
Is switched to the normal charge control mode.

In the normal charge control mode, the charge control circuit 5 is connected to the constant voltage control circuit 3 via the switch 4. At this time, the constant voltage control circuit unit 3 supplies a charging current while applying a constant voltage to the lithium ion secondary battery 7, and the charge control circuit unit 5 monitors the state of charge of the lithium ion secondary battery 7. When detecting the charge termination current indicating the completion of the charging, the charging control circuit unit 5 stops supplying the charging current to the constant voltage control circuit unit 3, and the charging ends.
In the normal charging control, charging can be performed in the constant current charging mode in which the charging current is kept constant, similarly to the constant voltage charging mode.

On the other hand, when the electric field level output from the detection circuit section 2 exceeds the threshold value, the CPU 6 switches the switch section 4 to the electromagnetic wave detection mode. In this electromagnetic wave detection mode, the CPU 6 connects to the constant voltage control circuit unit 3 via the switch unit 4, and the charge control circuit unit 5 sends the monitoring result of the charge state of the lithium ion secondary battery 7 to the CPU.
Tell 6

In the case of the electromagnetic wave detection mode, the CPU 6
The constant voltage control circuit 3 is instructed to lower the charging voltage (the charging current in the case of constant current charging).
Varies the internal resistance value according to this instruction, and reduces the charging voltage or charging current.

As shown in the state transition diagram of FIG. 2, the CPU 6 operates in a constant current charging mode which is a normal charging mode.
When the mode shifts from 21 or the constant voltage charging mode 22 to the electromagnetic wave detection mode 24, the electromagnetic wave detection counter is incremented by one and a timer (charge stop timer) is started at the same time.

When the timer (its value is α) times out a predetermined time and the CPU 6 times out, the CPU 6
The constant voltage control circuit 3 instructs the constant voltage control circuit 3 to stop (interrupt) charging, and upon receiving the instruction, the constant voltage control circuit 3 stops outputting the charging current. This state is the charge stop mode 25. By shifting to the charge stop mode, it is possible to avoid entering the dangerous charging area.

The CPU 6 starts the timer (monitoring return timer) at the same time as the transition to the charging stop mode 25. When the timer (the value thereof is γ) times out a predetermined time and times out, the value (α) of the charge stop timer and the value of the electromagnetic wave detection counter are reset, and the switch unit 4 is switched to perform normal charge control. Transition to mode. In the normal charge control mode, the shortage of the charge amount caused by the stop of the charge is supplemented, and the charge control circuit unit 5 detects the charge termination current to complete the charge (charge complete mode 23).

In the electromagnetic wave detection mode 24, if the charge control circuit 5 detects the charge termination current before the timeout of the charge stop timer, the mode shifts to the charge completion mode 23.

In the electromagnetic wave detection mode 24, if the electric field level of the interfering electromagnetic wave falls below the threshold before the timeout of the charging stop timer, the value (α) of the charging stop timer is reset, and the switch section 4 is reset. To switch to the normal charge control mode.

After resuming charging in the normal charge control mode, if the electric field level of the interfering electromagnetic wave exceeds the threshold value again, C
The PU 6 switches the switch unit 4 to the electromagnetic wave detection mode, increments the electromagnetic wave detection counter by one, and starts the charging stop timer.

When the electric field level of the disturbing electromagnetic wave exceeds the threshold value and returns to the threshold value or less in a short time (before the timeout of the charging stop timer), the electromagnetic wave detection mode 24 is switched to the normal mode. The charge control modes 21 and 22 are alternately repeated. At this time, every time the mode shifts to the electromagnetic wave detection mode 24, the value (X) of the electromagnetic wave detection counter is added. When the value (X) reaches the predetermined value (β), the CPU 6 immediately shifts to the charging stop mode 25, instructs the constant voltage control circuit unit 3 to stop charging, and sets the monitoring return timer. Start.

As described above, by shifting to the charging stop mode 25 based on the value of the electromagnetic wave detection counter, it is possible to avoid entering into a dangerous charging area that cannot be detected by the charging stop timer, and the battery can be charged together with the charge stop timer. Acts as a double protection measure to prevent overcharging of the battery.

In the electromagnetic wave detection mode 24, the time (α) at which the charging stop timer times out may be switched according to the electric field level of the interfering electromagnetic wave. In this case, a plurality of thresholds (a _n ; n = 1,
2, ‥) is stored, and an electric field level output from the detection circuit unit 2 (m) compared with the threshold value a _n, a ₁ <When _{m ≦ a 2 α = α 1} a 2 <m ≦ a when _{3 α} = _{α 2} ‥ _{(where, a n-1 <a n ,α} n-1> α n) as saying that, as the electric field level of the electromagnetic interference is high,
Α is set so that the time for the timeout of the charge stop timer becomes short.

As described above, this charging control device detects an externally disturbing electromagnetic wave and controls the charging voltage or charging current during charging in accordance with the detection, thereby protecting the battery from being overcharged due to the disturbing electromagnetic wave. can do. Further, when a shortage of the charge amount of the battery occurs due to the protection operation, the charge control for compensating for the shortage and securing a required charge rate can be performed.

Therefore, deterioration of the battery cycle life can be reduced, and a metal shield is not required, so that a product with a built-in battery can be reduced in size and weight.

(Second Embodiment) In the second embodiment,
A charge control method when the charge control device according to the first embodiment is incorporated in a wireless telephone device will be described.

When charging the lithium ion secondary battery during the period when the transmitter of the wireless telephone device stops transmitting, the externally-disturbed electromagnetic wave is detected by the method described in the first embodiment. When it is detected, the mode shifts to the electromagnetic wave detection mode, in which the charging voltage or the charging current is controlled, and the charging time until the charging is stopped is controlled.

On the other hand, when continuous transmission is performed from the transmitter of the wireless telephone device during charging, the electromagnetic wave accompanying the transmission has an adverse effect on charging similarly to the interfering electromagnetic wave. When a signal indicating the transmission output is obtained from the controller and it is recognized that the transmission is being performed, the mode shifts to the electromagnetic wave detection mode, in which the charging voltage or the charging current is controlled, and the charging time until the charging is stopped is controlled.

At this time, the charging time until the charging is stopped may be switched according to the power level at the time of transmission. In this case, as described above, a plurality of threshold values in the storage unit _{(a n; n = 1,2,} ‥) stores, compared with these threshold power level during transmission recognized from the transmission output of the transmitter . Then, the power level at the time of transmission belongs to which rank, and the charging time is set according to the rank.

When the transmitter of the wireless telephone device performs a TDMA transmission operation in which transmission is performed only during a time-divided transmission period, CPU 6 transmits a signal indicating that transmission has started during charging. When the recognition is made based on the transmission control signal generated inside the device, the switch unit 4 is switched to shift to the charging transmission mode 26 (FIG. 2).

In the charging transmission mode 26, charging is stopped during the time-divided transmission period, and charging is performed during periods other than the transmission period, and this is repeated. CPU6
Controls on / off of the charging based on the transmission control signal. When the charging is off, the constant voltage charging control circuit 3
The output of the charging current is stopped according to the instruction of PU6.

Further, the CPU 6 detects an externally-disturbed electromagnetic wave when charging is ON, and controls the charging voltage or the charging current to be suppressed when the disturbing electromagnetic wave is detected. When a charge termination current is detected through the charge control circuit 5, the mode shifts to the charge completion mode 23.

When the transmission operation of the transmitter is completed in the charging transmission mode 26, the mode shifts to the normal charging control mode.

As described above, according to this charging control method,
Even when the built-in battery is charged while transmitting from the wireless telephone device, overcharging of the battery can be prevented, and deterioration of battery performance can be suppressed.

In the embodiment, the charge control of the lithium ion secondary battery has been described. However, the present invention can be applied to the charge control of other secondary batteries.

The present invention is also applicable to devices with a built-in secondary battery other than the wireless telephone device.

[0056]

As is apparent from the above description, the charging control device and the charging control method of the present invention can prevent the battery from being overcharged by the influence of the electromagnetic wave during charging. A sufficient charge rate can be secured.

As a result, the deterioration of the battery performance can be suppressed, and the deterioration of the life of the battery cycle can be reduced. In addition, a metal shield for the charging circuit is not required, and the size and weight of the device with a built-in battery can be reduced.

The wireless telephone device of the present invention can prevent the battery from being overcharged and suppress the performance deterioration of the battery even when the built-in battery is charged while transmitting.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a charge control device according to an embodiment of the present invention;

FIG. 2 is a mode state transition diagram for explaining a charge control method according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Simple antenna 2 Detection circuit part 3 Constant voltage control circuit part 4 Switch part 5 Charge control circuit part 6 CPU 7 Lithium ion secondary battery 21 Constant current charge mode 22 Constant voltage charge mode 23 Charge completion mode 24 Electromagnetic wave detection mode 25 Charge stop Mode 26 Charge transmission mode

Claims (15)

[Claims] 1. A charging control device for controlling charging of a secondary battery, comprising: an electromagnetic wave monitoring means for detecting an electric field level of an electromagnetic wave arriving from the outside; and a charging current or charging based on a detection result of the electromagnetic wave by the electromagnetic wave monitoring means. A charge control device, comprising: control means for controlling a voltage. 2. The control device according to claim 1, further comprising: a comparing unit configured to compare the detected electric field level with a threshold value. The control unit controls a charging current or a charging voltage based on a comparison result of the comparing unit and controls the charging. The charging control device according to claim 1, wherein a charging time until the stop is controlled. 3. The comparison means ranks the electric field level by comparing the electric field level with a plurality of threshold values, and the control means determines a length of a charging time until the charging is stopped based on the rank. The charging control device according to claim 2, wherein the setting is performed. 4. The control means includes a counter for counting the number of times the charging current or the charging voltage has been controlled based on the detection result of the electromagnetic wave monitoring means, and the value of the counter is set to a predetermined value until the charging is completed. The charging control device according to claim 1, wherein the charging is stopped when the value reaches the value. 5. The charging device according to claim 2, wherein the control means includes a timer for counting a time from the stop of charging, and restarts charging after measuring a predetermined time by the timer. Charge control device. 6. A charging control method for controlling charging of a secondary battery, comprising detecting an electric field level of an electromagnetic wave arriving from outside, and suppressing a charging current or a charging voltage when the electric field level exceeds a threshold value. And a charging control method characterized by controlling a charging time until the charging is stopped. 7. The charging control method according to claim 6, wherein a charging time until the charging is stopped is set based on a magnitude of a voltage level of the electromagnetic wave. 8. Counting the number of times the charging current or the charging voltage is controlled based on the detection result of the electric field level of the electromagnetic wave, and stopping the charging when the number reaches a predetermined value halfway until the charging is completed. 7. The method according to claim 6, wherein
3. The charge control method according to 1. 9. The charge control method according to claim 6, wherein after the charging is stopped, the charging is restarted after a lapse of a predetermined time. 10. A wireless telephone device having a built-in secondary battery and a built-in transmitter for continuous transmission, wherein the transmitter is started when the transmitter is started while the secondary battery is being charged. A wireless telephone device comprising: charge control means for recognizing the electric field strength of the power level transmitted from the device and controlling the charging current or the charging voltage based on the recognition result. 11. The charging control means includes a comparing means for comparing the recognized electric field strength with a threshold value, wherein a charging current or a charging voltage is suppressed based on a comparison result of the comparing means, and the charging is performed. The wireless telephone device according to claim 10, wherein a charging time until the stop is controlled. 12. The charge control means ranks the electric field strength by comparing the electric field strength with a plurality of thresholds, and the charge control means determines a length of charge time until the charge stop based on the rank. 2. The method according to claim 1, wherein
2. The wireless telephone device according to 1. 13. The charge control device according to claim 11, wherein the charge control means includes a timer for counting a time from the stop of charging, and restarts charging after measuring a predetermined time by the timer. Wireless telephone device. 14. A wireless telephone device having a built-in secondary battery and a built-in transmitter for performing transmission in a TDMA system, wherein when the transmission by the transmitter is started while the secondary battery is being charged, A wireless telephone device, comprising: charge control means for stopping charging during a time-divided transmission period and performing charging during a non-transmission period based on a transmission control signal of the transmitter. 15. The wireless telephone device according to claim 10, wherein the secondary battery is a lithium ion secondary battery.