JPH0779535A - Residual capacity detection system for battery - Google Patents

Abstract

PURPOSE:To allow accurate detection of the residual capacity of a battery even during the charging or discharging operation thereof by taking advantage of the battery characteristics in a system comprising a secondary battery exhibiting the open voltage characteristics substantially proportional to the residual capacity of the battery. CONSTITUTION:The residual capacity detection system for battery comprises a switch 16 and a charge switching section 17 for turning the charging operation of a lithium ion secondary battery 11 ON/OFF, a battery voltage detecting section 13 for measuring the battery voltage at the time of OFF charging, and a section 14 for comparing the battery voltage at the time of OFF charging with a preset battery voltage (set battery voltage data) corresponding to a prescribed battery capacity to determine the battery capacity at the time of OFF charging thus detecting the residual capacity of battery under charging.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has a characteristic that an open battery voltage is almost proportional to the remaining capacity of the battery, such as a lithium ion secondary battery, a vanadium lithium secondary battery, a carbon lithium secondary battery, a lead storage battery, etc. The present invention relates to a battery remaining capacity detection method that is applied to electronic devices such as personal computers and word processors that include a secondary battery.

[0002]

2. Description of the Related Art Conventionally, in an electronic device equipped with a secondary battery and a battery remaining capacity detection mechanism, the battery remaining capacity is detected by measuring the battery voltage during charging / discharging, charging / discharging current and battery temperature. Was.

When detecting the full charge of a battery, the full charge is detected by detecting the battery voltage and the battery temperature at the end of charging. For example, in a nickel-cadmium battery, the battery voltage has a peak value at the end of charging, and the battery voltage has a characteristic of decreasing from this peak value. Therefore, in the past, full charge was detected by detecting the amount of battery voltage drop at the end of charging.

However, the lithium ion secondary battery cannot detect full charge by detecting the amount of battery voltage drop at the end of charging. Further, when the battery voltage during charging / discharging is measured and the battery residual capacity is obtained from the battery voltage during charging / discharging, the battery capacity cannot be accurately detected due to the internal resistance of the battery or the like.

[0005]

As described above, the lithium ion secondary battery cannot detect full charge by detecting the battery voltage drop at the end of charging. Further, when the battery voltage during charging / discharging is measured and the battery residual capacity is obtained from the battery voltage during charging / discharging, the battery capacity cannot be accurately detected due to the internal resistance of the battery or the like.

The present invention has been made in view of the above circumstances,
In a system including a rechargeable battery such as a lithium ion rechargeable battery, a vanadium lithium rechargeable battery, a carbon rechargeable lithium battery, a lead storage battery, etc., in which the open-circuit battery voltage is approximately proportional to the remaining capacity of the battery. An object of the present invention is to provide a battery remaining capacity detection method that can accurately detect the battery remaining capacity during charging and discharging by utilizing the characteristics.

[0007]

The present invention has a characteristic that the open-circuit battery voltage is approximately proportional to the remaining capacity of the battery, such as a lithium ion secondary battery, a vanadium lithium secondary battery, a carbon lithium secondary battery, and a lead storage battery. In a system equipped with a secondary battery, by utilizing this characteristic, it is possible to accurately detect the battery remaining capacity during charging and discharging, and as a means for controlling charging on / off. , Charging means provided with a means for measuring the battery voltage at the time of charging off, and means for comparing the measured battery voltage at the time of charging off with a battery voltage (set battery voltage data) according to a preset specified battery capacity, charging Remaining battery capacity during charging by determining the battery capacity when charging is off by comparing the battery voltage when charging is off and the set battery voltage data by measuring the battery voltage when charging is temporarily turned off Characterized in that it detects.

[0008]

According to the present invention, for example, in a system having a lithium ion secondary battery, the battery residual capacity at the time of charging is used by using the characteristic that the battery voltage when the lithium ion secondary battery is open is almost proportional to the battery residual capacity. Find out. That is, the lithium ion secondary battery is opened and the battery voltage at this time is detected. After the detection of the battery voltage when the battery is open, charging of the lithium ion secondary battery is restarted. The detected open battery voltage is compared with preset battery voltage data for which the preset battery capacity is known, the battery remaining capacity is obtained, and the battery remaining capacity is displayed and output. Further, full charge is detected from the remaining battery capacity at the time of charging, and when the battery is fully charged, the charging path is released and the charging is terminated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram showing the configuration of the first embodiment of the present invention. In FIG. 1, 11 is a lithium ion secondary battery. 12 is a constant voltage source with current limitation,
Here, the lithium ion secondary battery 11 is charged.
A battery voltage detector 13 detects the battery voltage of the lithium ion secondary battery 11.

Reference numeral 14 denotes a battery remaining capacity detection unit, which detects the battery remaining capacity and full charge of the lithium ion secondary battery 11, stores the battery voltage according to the known battery capacity in advance, and stores the battery voltage detection unit 13 therein. The battery voltage at the time of charging is detected by comparing with the battery voltage (setting battery voltage data) according to the known battery capacity stored in advance to detect the battery capacity at the time of charging off, and the battery remaining capacity is detected.

Reference numeral 15 denotes a display device for displaying data relating to the remaining capacity of the lithium-ion secondary battery 11. Here, the remaining battery capacity detected by the remaining battery capacity detector 14 is displayed and output.

Reference numeral 16 is a switch interposed in the charging current path of the lithium ion secondary battery 11, and turns on / off the charging of the lithium ion secondary battery 11 under the control of the charge switching unit 17.

Reference numeral 17 denotes a charge switching unit, which controls the switch 16 interposed in the charging current path of the lithium ion secondary battery 11 to be turned on / off under the control of the battery remaining capacity detection unit 14.

The operation of the first embodiment will be described. The constant voltage source 12 with current limitation is a lithium ion secondary battery 1
1 is charged at a constant voltage with a constant current or less.

When charging the lithium ion secondary battery 11, the charge switching section 17 turns on the switch 16. As a result, the output power of the constant voltage source 12 is switched to the switch 16
Is supplied to the lithium ion secondary battery 11 via the battery, and the lithium ion secondary battery 11 is charged with a constant voltage at a constant current or less.

At the time of charging, the fact that the battery voltage when the lithium ion secondary battery 11 is open is approximately proportional to the remaining capacity of the battery is utilized to check the remaining capacity of the battery during charging according to the following procedure.

The switch 16 is turned off by the charge switching unit 17, the charge current is temporarily cut off, and the charge is temporarily stopped.
The lithium ion secondary battery 11 is opened. The battery voltage at this time is detected by the battery voltage detection unit 13.

After the detection of the open battery voltage, the switch 16 is turned on again to restart the charging of the lithium ion secondary battery 11. The battery remaining capacity detection unit 14 compares the open battery voltage detected by the battery voltage detection unit 13 with a previously stored battery voltage (set battery voltage data) whose battery capacity is known to obtain a battery remaining capacity.

This battery remaining capacity data is displayed on the display unit 15.
To display the remaining battery capacity on the display device 15. In this way, the battery capacity at the time of charging the lithium ion secondary battery 11 is detected, and the battery remaining capacity is displayed.

Further, full charge is detected from the battery remaining capacity at the time of charging, and when the battery is fully charged, the charge switching unit 17 turns off the switch 16 to end the charging. As described above, according to the first embodiment, in a system including a lithium ion secondary battery which is a kind of secondary battery having a characteristic that the open battery voltage is substantially proportional to the remaining capacity of the battery,
Using the battery characteristics, the battery remaining capacity can be accurately detected during charging and the battery remaining capacity can be notified to the outside.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a circuit block diagram showing the configuration of the second embodiment of the present invention. In FIG. 2, reference numeral 21 is a lithium ion secondary battery. A constant voltage source 22 with current limitation charges the lithium-ion secondary battery 21. Two
3 is a battery voltage detection unit, which is a lithium ion secondary battery 2
The battery voltage of 1 is detected. Here, the battery voltage when the charging is off is detected according to the output of the timer 28.

Reference numeral 24 denotes a battery remaining capacity detection unit, which compares the measured battery voltage when the lithium-ion secondary battery 21 is charged off with a battery voltage whose preset battery capacity is known (set battery voltage data) and charges the battery. The battery capacity when the battery is off is determined to detect the battery remaining capacity and full charge of the lithium ion secondary battery 21. Here, the battery remaining capacity is detected at regular intervals.

Reference numeral 25 denotes a display device for displaying data relating to the remaining capacity of the lithium ion secondary battery 21. In this case, the remaining battery capacity detected by the remaining battery capacity detector 14 is displayed and output.

Reference numeral 26 is a switch interposed in the charging current path of the lithium-ion secondary battery 21, and turns on / off the charging of the lithium-ion secondary battery 21 under the control of the charge switching unit 27.

Reference numeral 27 denotes a charge switching unit, which controls ON / OFF of the switch 26 according to the control of the battery remaining capacity detection unit 24 and the timer 28. Reference numeral 28 denotes a timer, which controls the interval at which the charging of the lithium ion secondary battery 21 is turned off.

The operation of the second embodiment will be described here. The constant voltage source 22 with current limitation is used for the lithium ion secondary battery 2
1 is charged at a constant voltage with a constant current or less.

When charging the lithium ion secondary battery 21, the charge switching section 27 turns on the switch 26. During this charging, the lithium-ion secondary battery 21
Taking advantage of the fact that the battery voltage when the battery is open is approximately proportional to the remaining capacity of the battery, the remaining battery capacity during charging is investigated by the following procedure.

The timer 28 counts the remaining capacity of the lithium-ion secondary battery 21 at regular intervals by a timer counting operation according to a predetermined clock so that the remaining capacity of the lithium-ion secondary battery 21 is detected. Part 2
Send timer output signal to 4.

The charge switching section 27 turns off the switch 26 in response to a signal from the timer 28 to temporarily stop the supply of the charging current to the lithium ion secondary battery 21 to open the lithium ion secondary battery 21. To do.

The battery voltage at this time is detected by the battery voltage detection unit 23.
Detect by. After the detection of the battery voltage when open, the switch 26 is turned on again, and the lithium ion secondary battery 2
Recharge 1

The battery remaining capacity detection unit 24 compares the open battery voltage detected by the battery voltage detection unit 23 with a previously stored battery voltage of a known battery capacity (set battery voltage data) to obtain a battery remaining capacity. .

This battery remaining capacity data is displayed on the display device 25.
To display the remaining battery capacity on the display device 25.
In addition, full charge is detected from the remaining battery capacity when charging,
When the battery is fully charged, the charging switching unit 27 turns off the switch 26 to end the charging.

In this way, according to the output of the timer 28, the lithium ion secondary battery 21 in the charging mode is
The remaining capacity is detected at regular intervals. FIG. 3 is a circuit block diagram showing the configuration of the third embodiment of the present invention.

In FIG. 3, reference numeral 31 is a lithium ion secondary battery. A constant voltage source 32 with current limitation charges the lithium ion secondary battery 31. A battery voltage detector 33 detects the battery voltage of the lithium ion secondary battery 31. Here, the battery voltage when the charge is off is detected according to the output signal of the charge stop control unit 38.

Reference numeral 34 denotes a battery remaining capacity detection unit, which compares the measured battery voltage when the charging of the lithium-ion secondary battery 31 is off with a previously stored battery voltage (set battery voltage data) to charge the battery. The battery capacity when the battery is off is determined, and the remaining battery capacity and full charge of the lithium ion secondary battery 31 are detected.

Reference numeral 35 denotes a display device for displaying data relating to the remaining capacity of the lithium-ion secondary battery 31. In this case, the remaining battery capacity detected by the remaining battery capacity detector 34 is displayed and output.

Reference numeral 36 denotes a switch interposed in the charging current path of the lithium-ion secondary battery 31, and turns on / off charging of the lithium-ion secondary battery 31 under the control of the charge switching section 37.

Reference numeral 37 denotes a charge switching unit, which controls the switch 36 to be turned on / off under the control of the battery remaining capacity detection unit 34 and the charge stop control unit 38. Reference numeral 38 denotes a charge stop control unit that controls the interval at which the charging of the lithium ion secondary battery 31 is turned off, and changes the battery remaining capacity detection interval according to the battery remaining capacity detected by the battery remaining capacity detection unit 34.
Here, when the battery remaining capacity is small, the interval for battery remaining capacity detection is lengthened, and when the battery remaining capacity is high and the battery is near full charge, the interval for battery remaining capacity detection is shortened.

The operation of the third embodiment will be described. The constant voltage source 32 with current limitation is the lithium ion secondary battery 3
1 is charged at a constant voltage with a constant current or less.

When charging the lithium ion secondary battery 31, the charge switching section 37 turns on the switch 36. During this charging, the lithium-ion secondary battery 31
Taking advantage of the fact that the battery voltage when the battery is open is approximately proportional to the remaining capacity of the battery, the remaining battery capacity during charging is investigated by the following procedure.

The charge stop control unit 38 changes the battery remaining capacity detection interval according to the battery remaining capacity of the lithium ion secondary battery 31 detected by the battery remaining capacity detection unit 34. When the remaining battery capacity is low, the battery remaining capacity detection interval is lengthened, and when the remaining battery capacity is high and the battery is near full charge, the battery remaining capacity detection interval is shortened. A detection control signal is sent to each of the detection unit 33 and the battery remaining capacity detection unit 34.

In response to the detection control signal from the charge stop control unit 38, the charge switching unit 37 turns off the switch 36 to temporarily stop the supply of the charging current to the lithium ion secondary battery 21 to make the lithium ion secondary battery. 31 is opened.

The battery voltage at this time is detected by the battery voltage detection unit 33.
Detect by. After the detection of the battery voltage when the battery is opened, the switch 36 is turned on again to turn on the lithium ion secondary battery 3
Recharge 1

The battery remaining capacity detecting unit 34 compares the open battery voltage detected by the battery voltage detecting unit 33 with a battery voltage of a known battery capacity (set battery voltage data) in which the battery capacity is stored in advance to obtain the battery remaining capacity. .

This battery remaining capacity data is displayed on the display device 35.
To display the remaining battery capacity on the display device 35.
In addition, full charge is detected from the remaining battery capacity when charging,
When the battery is fully charged, the charging switching unit 37 turns off the switch 36 to end the charging.

In this way, under the control of the charge stop control unit 38, the remaining capacity of the lithium ion secondary battery 31 in the charging mode is detected at intervals according to the remaining capacity of the battery.

FIG. 4 is a circuit block diagram showing the configuration of the fourth embodiment of the present invention. In FIG. 4, 41 is a lithium ion secondary battery. Reference numeral 42 denotes a constant voltage source with current limitation, which charges the lithium ion secondary battery 41. Four
3 is a battery voltage detection unit, which is a lithium ion secondary battery 4
The battery voltage of 1 is detected.

Reference numeral 44 denotes a battery remaining capacity detecting section, which detects the battery remaining capacity and full charge of the lithium ion secondary battery 41. Here, the charging current is temporarily changed, and the battery voltage at the time when the charging current is zero ampere is obtained from the measured battery voltages with different charging currents, and this battery voltage is stored in advance as a known battery voltage (set battery voltage data). The remaining battery capacity during charging is detected by determining the remaining battery capacity when the charging current is zero ampere.

Reference numeral 45 denotes a display device for displaying data relating to the remaining capacity of the lithium-ion secondary battery 41. In this case, the remaining battery capacity detected by the remaining battery capacity detection unit 44 is displayed and output.

Reference numeral 46 denotes a charge switching unit which controls the switch 47 to be turned on / off under the control of the battery remaining capacity detection unit 44. Reference numeral 47 denotes a switch interposed in the charging current path of the lithium-ion secondary battery 41, and turns on / off charging of the lithium-ion secondary battery 41 under the control of the charge switching unit 46.

Reference numeral 48 denotes a charging current control unit, which is a constant voltage source 4
The charging current of the lithium-ion secondary battery 41 by 2 is temporarily variably controlled. Reference numeral 49 is a charging current detection unit that detects the charging current of the lithium-ion secondary battery 41.

The operation of the fourth embodiment will be described here. The constant voltage source 42 with current limitation is the lithium ion secondary battery 4
1 is charged at a constant voltage with a constant current or less.

When charging the lithium ion secondary battery 41, the switch 46 is turned on by the charge switching section 47. During this charging, the lithium ion secondary battery 41
Taking advantage of the fact that the battery voltage when the battery is open is approximately proportional to the remaining capacity of the battery, the remaining battery capacity during charging is investigated by the following procedure.

The charging current controller 48 changes the limiting current value of the current limiting function of the constant voltage source 42 to temporarily change the charging current. The charging current detection unit 49 detects the charging current due to the charging current change, and the battery voltage detection unit 43 also detects the battery voltage.

After the detection of the charging current and the battery voltage due to the change of the charging current is completed, the charging current is returned to the state before the change. The charging current detection unit 49 and the battery voltage detection unit 43 detect the charging current and the battery voltage after returning to the state before the change of the charging current.

The battery remaining capacity detection unit 44 detects the charging current at zero ampere from each battery voltage having different charging currents before and after the charging current change detected by the charging current detection unit 49 and the battery voltage detection unit 43. Find the battery voltage of. The remaining battery capacity during charging is detected by comparing the battery voltage when the charging current is zero amperes with a preset known battery voltage to obtain the battery capacity when the charging current is zero amperes.

This battery remaining capacity data is displayed on the display device 45.
To display the remaining battery capacity on the display device 45.
In addition, full charge is detected from the remaining battery capacity when charging,
When the battery is fully charged, the charging switching unit 46 turns off the switch 47 to end the charging.

In this way, the charging current is temporarily changed, the battery voltage at the time when the charging current is zero ampere is obtained from the measured battery voltages having different charging currents, and the battery voltage is set to the known battery voltage set in advance. The remaining battery capacity during charging is detected by determining the remaining battery capacity when the charging current is zero ampere.

FIG. 5 is a circuit block diagram showing the configuration of the fifth embodiment of the present invention. In FIG. 5, reference numeral 51 is a lithium ion secondary battery. Reference numeral 52 is a constant voltage source with current limitation, which charges the lithium ion secondary battery 51. 5
3 is a battery voltage detection unit, which is a lithium ion secondary battery 5
The battery voltage of 1 is detected.

Reference numeral 54 denotes a battery remaining capacity detecting section, which detects the battery remaining capacity and full charge of the lithium ion secondary battery 51. Here, the charging current is temporarily changed at fixed time intervals, and the battery voltage at the time when the charging current is zero ampere is obtained from the measured battery voltage at which the charging current is different, and the same battery voltage is set to a preset known battery voltage. By comparison, the battery capacity when the charging current is zero amperes is obtained, and the battery remaining capacity is detected at regular intervals.

Reference numeral 55 denotes a display device for displaying data relating to the remaining capacity of the lithium-ion secondary battery 51. Here, the remaining battery capacity detected by the remaining battery capacity detection unit 54 is displayed and output.

Reference numeral 56 is a charge switching unit, which controls ON / OFF of the switch 57 under the control of the battery remaining capacity detection unit 54. Reference numeral 57 denotes a switch interposed in the charging current path of the lithium-ion secondary battery 51, and turns on / off charging of the lithium-ion secondary battery 51.

Reference numeral 58 is a charging current control unit, which is a timer 60.
The charging current of the lithium-ion secondary battery 51 by the constant voltage source 52 is temporarily variably controlled according to the clock output signal output at more constant time intervals.

Reference numeral 59 denotes a charging current detecting section interposed in the charging current path of the lithium ion secondary battery 51, and detects the charging current of the lithium ion secondary battery 51. Reference numeral 60 denotes a timer, which outputs a time count output signal to the charging current control unit 58 at a constant time interval to control the interval at which the charging current of the lithium ion secondary battery 51 is temporarily changed.

The operation of the fifth embodiment will be described here. The constant voltage source 52 with current limitation is the lithium ion secondary battery 5
1 is charged at a constant voltage with a constant current or less.

When charging the lithium-ion secondary battery 51, the charge switching unit 57 turns on the switch 56.
At the time of this charging, the battery residual capacity at the time of charging is examined by the following procedure by utilizing the characteristic that the battery voltage when the lithium ion secondary battery 51 is open is almost proportional to the residual capacity of the battery.

The timer 60 is the lithium ion secondary battery 5
A signal is sent to the charging current controller 58 so that the remaining capacity of 1 is detected at regular intervals. The charging current control unit 58 is
The signal from the timer 60 changes the limiting current value of the current limiting function of the constant voltage source 52 to temporarily change the charging current.

The charging current and the battery voltage after the change of the charging current are detected by the charging current detector 59 and the battery voltage detector 53. After the detection of the charging current and the battery voltage after the change of the charging current is completed, the charging current before the change is restored.

The charging current detecting unit 59 and the battery voltage detecting unit 53 detect the charging current and the battery voltage after the charging current returns to the state before the change. The battery remaining capacity detection unit 54 determines the battery voltage at the time of zero amperage of charging current by the battery voltage detected by the charging current detection unit 59 and the battery voltage detection unit 53 before and after the charging current change and different charging currents. Ask. The remaining battery capacity during charging is detected by comparing the battery voltage when the charging current is zero amperes with a preset known battery voltage to obtain the battery capacity when the charging current is zero amperes.

This battery remaining capacity data is displayed on the display device 55.
To display the remaining battery capacity on the display device 55.
In addition, full charge is detected from the remaining battery capacity when charging,
When the battery is fully charged, the charging switching unit 56 turns off the switch 57 to end the charging.

In this way, the charging current is temporarily changed at fixed time intervals, the battery voltage at the time when the charging current is zero ampere is obtained from the measured battery voltages having different charging currents, and the battery voltage is preset. The battery capacity at the time when the charging current is zero ampere is calculated by comparing with the known battery voltage, and the battery remaining capacity is detected at regular intervals.

FIG. 6 is a circuit block diagram showing the configuration of the sixth embodiment of the present invention. In FIG. 6, reference numeral 61 is a lithium ion secondary battery. Reference numeral 62 denotes a constant voltage source with current limitation, which charges the lithium ion secondary battery 1. 6
3 is a battery voltage detection unit, which is a lithium-ion secondary battery 6
The battery voltage of 1 is detected.

Reference numeral 64 denotes a battery remaining capacity detection unit, which detects the battery remaining capacity and full charge of the lithium ion secondary battery 61. Here, the charging current is changed at time intervals according to the remaining capacity of the battery, the battery voltage at the time when the charging current is zero amperes is obtained from the measured battery voltage with different charging currents, and the same battery voltage is stored in advance as a known battery voltage. Compared with the above, the battery capacity at the time of zero ampere charging current is determined and the battery remaining capacity is detected.The battery remaining capacity is detected by changing the battery remaining capacity detection interval according to the battery remaining capacity. .

Reference numeral 65 denotes a display device for displaying data relating to the remaining capacity of the lithium-ion secondary battery 61. Here, the remaining battery capacity detected by the remaining battery capacity detection unit 64 is displayed and output.

Reference numeral 66 denotes a charge switching unit which controls the switch 67 to be turned on / off under the control of the battery remaining capacity detection unit 64. 67 is a switch interposed in the charging current path of the lithium-ion secondary battery 61.
Turn charging to 1 on / off.

Reference numeral 68 denotes a charging current control unit, which controls the charging current of the lithium ion secondary battery 61 by the constant voltage source 62 under the control of the charging current change control unit 70. Reference numeral 69 is a charging current detection unit interposed in the charging current path of the lithium ion secondary battery 61, and detects the charging current of the lithium ion secondary battery 61.

Reference numeral 70 denotes a charging current change control unit, which controls the interval at which the charging current of the lithium ion secondary battery 61 is changed according to the remaining capacity of the battery. Here, when the remaining battery capacity of the lithium-ion secondary battery 61 is small, the interval at which the remaining battery capacity is detected is lengthened, and when the remaining battery capacity is large and near full charge, the interval at which the remaining battery capacity is detected is shortened. The charging current control unit 68 is controlled as described above.

The operation of the sixth embodiment will be described here. The constant voltage source 62 with current limitation is the lithium ion secondary battery 6
1 is charged at a constant voltage with a constant current or less.

When charging the lithium-ion secondary battery 61, the charge switching unit 67 turns on the switch 66.
At the time of this charging, the battery residual capacity at the time of charging is checked by the following procedure by utilizing the characteristic that the battery voltage when the lithium ion secondary battery 61 is open is almost proportional to the residual capacity of the battery.

The charging current change controller 70 controls the interval at which the charging current of the lithium ion secondary battery 61 is changed according to the battery remaining capacity detected by the battery remaining capacity detector 64. When the remaining battery capacity of the secondary battery 61 is small, the interval for detecting the remaining battery capacity is lengthened, and when the remaining battery capacity is large and the battery is close to full charge, the interval for detecting the remaining battery capacity is shortened.
A control signal is output to the charging current control unit 68.

The charging current control unit 68 changes the limiting current value of the current limiting function of the constant voltage source 2 in response to the control signal from the charging current change control unit 70 to temporarily change the charging current.

The charge current detector 69 and the battery voltage detector 63 detect the charge current and the battery voltage after the change of the charge current. After the detection of the charging current and the battery voltage after the change of the charging current is completed, the charging current before the change is restored.

The charging current detecting unit 69 and the battery voltage detecting unit 63 detect the charging current and the battery voltage after the charging current returns to the state before the change. The battery remaining capacity detection unit 64 determines the battery voltage at the time of zero ampere charging current by the battery voltage detected by the charging current detection unit 69 and the battery voltage detection unit 63 before and after the charging current change and different charging currents. Ask. The remaining battery capacity during charging is detected by comparing the battery voltage at the time of zero ampere of the charging current with a known battery voltage stored in advance to obtain the battery capacity at the time of zero ampere of the charging current.

This battery remaining capacity data is displayed on the display device 65.
To display the remaining battery capacity on the display device 65.
In addition, full charge is detected from the remaining battery capacity when charging,
When the battery is fully charged, the charge switching unit 66 turns off the switch 67 to end the charging.

In this way, the battery remaining capacity is detected by changing the time interval according to the battery remaining capacity. That is, the charging current is temporarily changed at a time interval according to the remaining capacity of the battery, the battery voltage when the charging current is zero ampere is obtained from the measured battery voltage at which the charging current is different, and this battery voltage is set to a preset known value. The battery capacity at the time when the charging current is zero amperes is calculated by comparing with the battery voltage of 1 to detect the remaining battery capacity.

FIG. 7 is a circuit block diagram showing the configuration of the seventh embodiment of the present invention. In FIG. 7, reference numeral 71 is a lithium ion secondary battery. Reference numeral 72 denotes a load circuit of the battery 71, and here, a load accompanied by load fluctuation is targeted. A battery voltage detector 73 detects the battery voltage of the lithium ion secondary battery 71.

Reference numeral 74 denotes a battery remaining capacity detecting section, which detects the battery remaining capacity of the lithium ion secondary battery 71.
Here, the load circuit 7 detected by the discharge current detector 76 is detected.
The battery voltage at zero amperage of the charging current is obtained from the battery voltage data of two different discharging currents due to the load fluctuation,
This battery voltage is compared with a known battery voltage stored in advance to obtain the battery capacity when the charging current is zero ampere, and the battery remaining capacity is detected. Reference numeral 75 denotes a display device, which displays data relating to the remaining capacity of the lithium ion secondary battery 71. Here, the remaining battery capacity detected by the remaining battery capacity detection unit 74 is displayed and output.

Reference numeral 76 is a discharge current detection unit, which detects the discharge current of the lithium ion secondary battery 71. Here, the operation of the seventh embodiment will be described.

Electric power is supplied to the load circuit 72 from the lithium ion secondary battery 71. Using the characteristic that the battery voltage when the lithium-ion secondary battery 71 is open is approximately proportional to the remaining capacity of the battery, the remaining capacity of the battery when discharged is examined by the following procedure.

The battery remaining capacity detecting unit 74 obtains the battery voltage at zero discharge current from the battery voltage data of two or more kinds having different discharge currents detected by the discharge current detecting unit 76 and the battery voltage detecting unit 73. The battery remaining capacity is detected by comparing the battery voltage with a known battery voltage stored in advance.

This battery remaining capacity data is displayed on the display device 75.
To display the remaining battery capacity on the display device 75. In this way, the battery capacity is detected when the lithium ion secondary battery 71 is discharged, and the detected battery remaining capacity is displayed and output.

FIG. 8 is a circuit block diagram showing the configuration of the eighth embodiment of the present invention. In FIG. 8, reference numeral 81 is a lithium ion secondary battery. Reference numeral 82 is a load circuit accompanied by load fluctuation. A battery voltage detection unit 83 detects the battery voltage of the lithium ion secondary battery 81.

Reference numeral 84 denotes a battery remaining capacity detecting portion, which detects the battery remaining capacity of the lithium ion secondary battery 81.
Here, the load circuit 82 detected by the discharge current detection unit 86 according to the start signal output from the timer 87 at regular intervals.
From a plurality of battery voltage data of different discharge currents due to load fluctuations, the battery voltage at the time of charging current zero amperes is obtained, and this battery voltage is compared with a previously stored known battery voltage,
Obtain the battery capacity when the charging current is zero amperes and detect the remaining battery capacity.

Reference numeral 85 denotes a display device for displaying data relating to the remaining capacity of the lithium ion secondary battery 81. Here, the remaining battery capacity detected by the remaining battery capacity detection unit 84 is displayed and output.

Reference numeral 86 is a discharge current detection unit, which detects the discharge current of the lithium ion secondary battery 81. Reference numeral 87 denotes a timer, which controls the interval at which the battery remaining capacity detection unit 84 detects the remaining capacity of the lithium ion secondary battery 81 at a constant interval.

The operation of the eighth embodiment will be described here. Electric power is supplied to the load circuit 82 from the lithium ion secondary battery 81. Using the characteristic that the battery voltage when the lithium-ion secondary battery 81 is open is almost proportional to the remaining capacity of the battery, the remaining capacity of the battery when discharged is examined by the following procedure.

The timer 87 is a lithium ion secondary battery 8
A signal is sent to the battery remaining capacity detection unit 84 so that the remaining capacity detection of 1 is performed at regular intervals. When a signal is sent from the timer 87, the battery remaining capacity detection unit 84 receives the discharge current from the battery voltage data of two or more types having different discharge currents detected by the discharge current detection unit 86 and the battery voltage detection unit 83. Find the battery voltage at zero amps. This battery voltage is compared with a known battery voltage stored in advance to detect the battery remaining capacity.

This battery remaining capacity data is displayed on the display device 85.
To display the remaining battery capacity on the display device 85. In this way, at regular intervals according to the control of the timer 87,
The battery capacity is detected when the lithium ion secondary battery 81 is discharged, and the detected battery remaining capacity is displayed.

FIG. 9 is a circuit block diagram showing the configuration of the ninth embodiment of the present invention. In FIG. 9, 91 is a lithium ion secondary battery. Reference numeral 92 is a load circuit accompanied by load fluctuation. A battery voltage detector 93 detects the battery voltage of the lithium ion secondary battery 91.

Reference numeral 94 denotes a battery remaining capacity detecting section, which detects the battery remaining capacity of the lithium ion secondary battery 91.
Here, the battery voltage at the time of zero ampere of the charging current is obtained from the plurality of battery voltage data of different discharging currents detected by the discharging current detection unit 96, which are detected by the discharging current detecting unit 96 at variable time intervals according to the remaining capacity of the battery. Then, this battery voltage is compared with a known battery voltage stored in advance, the battery capacity at the charging current of zero ampere is calculated, and the battery remaining capacity is detected.

Reference numeral 95 denotes a display device for displaying data relating to the remaining capacity of the lithium-ion secondary battery 91. Here, the remaining battery capacity detected by the remaining battery capacity detection unit 94 is displayed and output.

A discharge current detector 96 detects the discharge current of the lithium ion secondary battery 91. Reference numeral 97 denotes a battery remaining capacity detection control unit, which is a lithium ion secondary battery 91
The interval at which the remaining battery capacity is detected is variably controlled according to the remaining battery capacity. Here, a signal is sent to the battery remaining capacity detection unit 94 so as to lengthen the interval for detecting the battery remaining capacity when the remaining capacity of the battery is large and shorten the interval for detecting the remaining capacity of the battery when the remaining capacity of the battery is small. send.

The operation of the ninth embodiment will be described here. Electric power is supplied to the load circuit 92 from the lithium ion secondary battery 91. By utilizing the characteristic that the battery voltage when the lithium ion secondary battery 91 is open is almost proportional to the remaining capacity of the battery,
Follow the procedure below to check the remaining battery capacity during discharge.

The battery remaining capacity detection control unit 97 varies the time interval of the battery remaining capacity detection according to the remaining capacity of the lithium ion secondary battery 91. Here, when the battery remaining capacity is large, the battery remaining capacity detection is performed. Make the interval longer,
When the battery remaining capacity is low, a signal is sent to the battery remaining capacity detection unit 94 so as to shorten the interval for battery remaining capacity detection.

When a signal is sent from the battery remaining capacity detection control section 97, the battery remaining capacity detection section 94 uses the battery voltage data of different discharge currents detected by the discharge current detection section 96 and the battery voltage detection section 93. , Calculate the battery voltage at zero ampere discharge current. This battery voltage is compared with a known battery voltage stored in advance to detect the battery remaining capacity.

This battery remaining capacity data is displayed on the display device 95.
To display the remaining battery capacity on the display device 95. In this way, battery remaining capacity detection is performed at time intervals that vary depending on the remaining capacity of the lithium ion secondary battery 91.

In each of the above-described embodiments, the lithium ion secondary battery is taken as an example to detect the battery remaining capacity. However, for example, a vanadium lithium secondary battery, a carbon lithium secondary battery, a lead storage battery, etc. The present invention can be applied to a system including another secondary battery having a characteristic that the battery voltage when opened is almost proportional to the remaining capacity of the battery, as in the above embodiment.

Further, in the seventh, eighth and ninth embodiments, the load circuit accompanied by load fluctuation is shown as an example, but the load fluctuation does not occur in a short time (the load current does not change in a short time).
For the load, a circuit configuration may be used in which the load current is temporarily changed from the outside when the battery remaining capacity is detected.

[0109]

As described in detail above, according to the present invention, not only the detection of full charge but also the use of the characteristic that the battery voltage when the lithium ion secondary battery is open is almost proportional to the remaining capacity of the battery, Since the remaining capacity of the battery during charging / discharging can be accurately known, display of the remaining capacity of the battery, detection of charging time until full charge, detection of system drive time by the battery, etc. can be performed with high reliability.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a configuration of a second embodiment of the present invention.

FIG. 3 is a circuit block diagram showing a configuration of a third embodiment of the present invention.

FIG. 4 is a circuit block diagram showing a configuration of a fourth embodiment of the present invention.

FIG. 5 is a circuit block diagram showing a configuration of a fifth embodiment of the present invention.

FIG. 6 is a circuit block diagram showing the configuration of a sixth embodiment of the present invention.

FIG. 7 is a circuit block diagram showing a configuration of a seventh embodiment of the present invention.

FIG. 8 is a circuit block diagram showing a configuration of an eighth embodiment of the present invention.

FIG. 9 is a circuit block diagram showing a configuration of a ninth embodiment of the present invention.

[Explanation of symbols]

11, 21, 31, 41, 51, 61, 71, 81, 9
1 ... Lithium ion secondary battery, 12, 22, 32, 4
2, 52, 62 ... Constant voltage source with current limitation, 13, 2
3, 33, 43, 53, 63, 73, 83, 93 ... Battery voltage detection unit, 14, 24, 34, 44, 54, 64, 7
4, 84, 94 ... Battery remaining capacity detection unit, 15, 25, 3
5, 45, 55, 65, 75, 85, 95 ... Display device,
16, 26, 36, 47, 57, 67 ... Switch, 1
7, 27, 37, 46, 56, 66 ... Charge switching unit, 2
8, 60, 87 ... Timer, 38, ... Charge stop control unit, 4
8, 58, 68 ... Charging current controller, 49, 59, 69 ...
Charging current detector, 70 ... Charging current change controller, 72, 8
2, 92 ... Load circuit, 76, 86, 96 ... Discharge current detection unit, 97 ... Battery remaining capacity detection control unit.

Claims (9)

[Claims] 1. A system for charging a secondary battery, which has a characteristic that the battery voltage when open is almost proportional to the remaining capacity of the battery, and means for controlling the charging on / off and measuring the battery voltage when the charging is off. And a means for comparing the measured battery voltage at the time of charging off with a battery voltage according to a preset specified battery capacity, measure the battery voltage by temporarily turning off charging during charging, and charge the battery. A battery remaining capacity detection method characterized in that the remaining battery capacity during charging is detected by comparing the battery voltage at the time of off and the set battery voltage to obtain the battery capacity at the time of charging off. 2. In a system for charging a secondary battery having a characteristic that an open battery voltage is substantially proportional to the remaining capacity of the battery, a means for controlling on / off of charging and a charge on / off interval are controlled. Means, means for measuring the battery voltage when charging is off, and means for comparing the measured battery voltage when charging is off with the battery voltage according to a preset specified battery capacity, and the charging is temporarily turned off during charging. Then, the battery voltage is measured, and the measured battery voltage at the time of charging off is compared with the battery voltage at which the preset battery capacity is known to obtain the battery capacity at the time of charging off. The battery remaining capacity detection method is characterized by detecting the remaining capacity of the battery during charging. 3. In a system for charging a secondary battery, which has a characteristic that the battery voltage when open is almost proportional to the remaining capacity of the battery, means for turning on / off charging and means for controlling the charging on / off interval. And a means for measuring the battery voltage at the time of charging off and a means for comparing the measured battery voltage at the time of charging off with a battery voltage according to a preset specified battery capacity, by temporarily turning off the charging during charging. Measure the battery voltage and compare the measured battery voltage when charging is off with the battery voltage for which the preset battery capacity is known to obtain the battery capacity when charging is off. A battery remaining capacity detection method, which detects the remaining capacity of the battery during charging by changing it according to. 4. In a system for charging a secondary battery having a characteristic that an open battery voltage is substantially proportional to the remaining capacity of the battery, a charging current changing means, a charging current detecting means, and a battery voltage. The means for detecting the charging current, the means for temporarily changing the charging current, and the means for obtaining the battery voltage when the charging current is zero ampere from the detected battery voltage at which the charging current is different, and the battery voltage when the charging current is zero ampere are preset. The battery voltage at the time of zero ampere of the charging current is obtained from the measured battery voltage at which the charging current is different when the charging current is changed, and the battery voltage is preset. Compared to the known battery voltage
A battery remaining capacity detection method that detects the battery remaining capacity during charging by determining the battery capacity when the charging current is zero ampere. 5. In a system for charging a secondary battery having a characteristic that a battery voltage when open is almost proportional to the remaining capacity of the battery, a means for changing a charging current and a means for controlling an interval for changing the charging current. And means for detecting the rechargeable battery,
The means to detect the battery voltage and the charging current detected by changing the charging current are different.The means to obtain the battery voltage at the non-charging current where the charging current does not flow from the sensing battery voltage, The battery voltage at the time of zero ampere of the charging current is obtained from the measured battery voltage, which has a means for comparing with the battery voltage according to the preset specified battery capacity and the charging current when the charging current is changed, and the same battery voltage. Is compared with a known battery voltage set in advance to determine the battery capacity when the charging current is zero amperes, and the battery remaining capacity is detected at regular intervals to detect the battery remaining capacity during charging. Battery remaining capacity detection method. 6. In a system for charging a secondary battery having a characteristic that a battery voltage when open is approximately proportional to the remaining capacity of the battery, a means for changing a charging current and a means for controlling an interval for changing the charging current. And means for detecting the charging current,
The means to detect the battery voltage and the charging current detected by changing the charging current are different.The means to obtain the battery voltage at the non-charging current where the charging current does not flow from the sensing battery voltage, A means for comparing with a battery voltage according to a preset specified battery capacity is provided, and the battery voltage when the charging current is zero ampere is obtained from the battery voltage at which the charging current is different when the charging current is changed. The battery capacity at the time when the charging current is zero amperes is calculated by comparing with the set known battery voltage, and the battery remaining capacity during charging is detected by changing the interval of the battery remaining capacity detection according to the battery remaining capacity. A battery remaining capacity detection method characterized by the following. 7. A discharge current detecting means and a battery voltage detecting means in a system using a secondary battery as a drive source, which has a characteristic that an open battery voltage is substantially proportional to the remaining capacity of the battery. The charging current is changed by changing the charging current. A means for obtaining the battery voltage at the non-charging current in which the charging current does not flow from the detected battery voltage, and the battery voltage at the non-charging current according to the preset specified battery capacity. A means for comparing with the battery voltage is provided, and the battery voltage at a discharge current of zero ampere is obtained from the battery voltage at which the discharge current is different, and the battery voltage at a discharge current of zero ampere and the preset battery capacity are compared with the known battery voltage. A battery remaining capacity detection method, which detects the battery remaining capacity during discharging by comparing and determining the battery capacity at zero ampere discharge current. 8. A discharge current detecting means and a battery voltage detecting means in a system using a secondary battery as a drive source, which has a characteristic that an open battery voltage is substantially proportional to the remaining capacity of the battery. A means for obtaining a battery voltage at a non-charging current in which a discharging current does not flow from a plurality of detection battery voltages having different discharging currents, and a means for comparing the battery voltage at the no-charging current with a battery voltage according to a preset specified battery capacity The battery voltage at the time of discharge current zero amperes is determined from the battery voltage at which the discharge current is different, and the battery voltage at the time of discharge current zero amperes and the preset battery capacity are compared with each other, and
A battery remaining capacity detection method characterized in that the battery remaining capacity during discharging is detected by determining the battery capacity when the discharge current is zero ampere and performing the battery remaining capacity detection at regular intervals. 9. In a system using a secondary battery as a drive source, which has a characteristic that the battery voltage when open is almost proportional to the remaining capacity of the battery, means for detecting discharge current, and means for detecting battery voltage, A means for obtaining a battery voltage at a non-charging current in which a discharging current does not flow from a plurality of detection battery voltages having different discharging currents, and a means for comparing the battery voltage at the no-charging current with a battery voltage according to a preset specified battery capacity The battery voltage when the discharge current is zero ampere is obtained from the battery voltage at which the discharge current is different, and the battery voltage when the discharge current is zero ampere and the preset battery capacity data are compared, and the discharge is performed. The present invention is characterized in that the battery remaining capacity during discharging is detected by obtaining the battery capacity at zero ampere of current and changing the interval for performing the battery remaining capacity detection according to the battery remaining capacity. Battery remaining capacity detection method.