JP3372901B2 - Battery charger and battery charge detection control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charge control technique, and in particular, determines a level of a charge state from a charge start state to a charge completion state by even distribution and notifies a user of an accurate charge state level. The present invention relates to a possible battery charger and a battery charge detection control method.

[0002]

2. Description of the Related Art As a conventional technique of a battery charger capable of surely detecting the mounting and full charge of a battery by checking a charging current and a voltage between charging terminals, there is, for example, one disclosed in Japanese Patent Laid-Open No. 8-168188. is there. That is, the related art disclosed in Japanese Patent Laid-Open No. 8-168188 discloses a charging control unit having a charging current detecting unit for detecting a charging current of a battery and a voltage detecting unit for detecting a voltage of the battery, and a charging terminal for connecting the battery. In the battery charger for charging the battery, the charging control unit reads the charging current detected by the charging current detection unit and the terminal voltage detected by the voltage detection unit, and determines whether the battery is attached or not. And a full charge determining means for determining whether or not charging is completed based on the value of the charging current. In such a battery charger, the full charge determination means is
A full charge charge current band consisting of a current value Ax and a current value Ay (Ax> Ay) is set near the threshold A1 of the charge current when the battery is fully charged, and the charge current detected by the charge current detector is charged. It has a function to detect that the battery has passed through the current band, determine that the charging is completed, and when the charging current decreases without detecting the passage of the fully charged current band, to judge that the battery has been removed from the battery charger. However, the detection switch (or mounting detection terminal) for battery mounting detection is performed by detecting the battery mounting, charging progress and full charge by using the characteristic that the charging current decreases as the battery charging progresses. It is disclosed that a class is not required, the number of parts is reduced, the mechanical design is easy, and the cost is reduced. Further, it is disclosed that holes (eg, switches) (or terminals) are reduced in the case of the battery charger, the shape is simplified, and the battery is resistant to troubles due to external factors such as mechanical or static electricity. In addition, since the voltage and charging current between the charging terminals are alternately and repeatedly checked, there are few false detections even when the battery mounting mechanism is not fitted properly or the hardware operation is unstable, and it is possible to confirm that the battery has been mounted securely. The effect of being detectable is disclosed. Further, the current band (Ax to Ay) is set in the vicinity of the threshold of full charge, and it is determined that the charging current has passed through the current band (Ax to Ay) to determine the full charge (charging completed). There is disclosed an effect that it is possible to make a reliable judgment without erroneous detection due to the influence of vibration of the.

[0003]

However, in the prior art, although the charge state can be grasped to some extent by monitoring the battery voltage, the lithium ion battery is not fully charged when it reaches a certain charge level. Since there is almost no voltage change that is almost equal to the voltage of, the charge level near full charge becomes very long even if an accurate voltage detection circuit is used, and it is impossible to notify the user of the charge level accurately. There was a problem that it was possible.
In addition, when notifying the user of the level of several kinds of charge status, it is expressed by several colors of LEDs, and the battery is charged from the empty state, such as "red (battery empty) → orange → yellow green → green (full charge)" When expressed as “red” even if a highly accurate voltage detection circuit is used
There was a problem that the "orange" time was short and the "yellow-green" state became extremely long, and the level of the charge state could not be notified with accurate and even distribution.

The present invention has been made in view of the above problems, and an object of the present invention is to determine the level of the charge state from the charge start state to the charge complete state by evenly distributing the charge state to determine an accurate charge state. There is a point to provide a battery charger and a battery charge detection control method capable of notifying a user of the battery level.

[0005]

The gist of the invention described in claim 1 is to judge the level of the charging state from the charging start state to the charging completion state by even distribution and notify the user of the accurate charging state level. A battery charger capable of performing constant-current charging and constant-voltage charging of the battery, a resistor that generates a voltage according to the charging current of the battery, and constant-voltage charging of the battery During the constant voltage charging control period, the battery voltage of the battery is detected based on the voltage across the battery to generate and output the data of the battery voltage. a battery voltage detecting circuit, generating data of the charge current during constant voltage charging control section that performs constant-voltage charge is detected based on a voltage generated in the resistor by the constant charging <br/> voltage of said battery - a charging current detection circuit for outputting, prior to
The data of each of the plurality of battery voltages and the constant charging voltage is collected, and the control for switching from the constant current charging control to the constant voltage charging control is performed in the process of reaching the full charge of the battery. A control unit that detects that the charging current is lower than or equal to the charging current based on the voltage generated in the resistor and detects the completion of charging of the battery, and the charging state in the process until the completion of charging of the battery according to the instruction of the control unit. The battery charger is characterized by having a display unit for displaying and notifying the user of an accurate charging state. The gist of the invention according to claim 2 is that the battery voltage detection circuit is
The battery charger according to claim 1 , wherein the battery voltage is measured during the current charging control section . The gist of the invention according to claim 3 is that the charging current detection circuit includes a comparator that sets a voltage value corresponding to each of the plurality of charging currents and the constant charging current to a threshold level, and the resistance is used in the comparator. The battery charger according to claim 1, wherein the battery charger is configured to detect an output voltage from the charger and transmit the detection result to the control unit. The gist of the invention according to claim 4 is that the control unit controls the data of each of the plurality of battery voltages generated and output by the battery voltage detection circuit and the plurality of charges generated and output by the charging current detection circuit. Current, and above
4. The display unit is configured to notify the user of the state of charge during charging in the process up to the completion of charging of the battery based on the constant charge current data. The battery charger according to any one of 1. SUMMARY OF THE INVENTION according to claim 5, wherein the control unit that executes charging control of the battery, the battery was treated with constant current charge control in the constant current charging control section, the constant current charging reaches a certain voltage with the battery voltage The control is switched to a constant voltage charging control at the end timing of the control section, and it is configured to finish the charging control of the battery when it is determined that the battery is fully charged with the constant charging current. The battery charger according to any one of 1. The gist of the invention according to claim 6 is a battery charge detection control method capable of determining the level of the charge state from the charge start state to the charge completed state by even distribution and notifying the user of the accurate state of the charge state. Constant current charging and constant current
A charging step of performing pressure charging, a charging current-voltage converting step of generating a voltage according to the charging current of the battery using a resistor, and a constant voltage charging control section performing constant voltage charging of the battery. A battery voltage detection step of generating and outputting data of each of the plurality of battery voltages by detecting each of the plurality of battery voltages of the battery based on the voltage across the battery,
A charging current detection step of the charging current to the constant voltage charging control section is performing constant voltage charging is detected on the basis of the voltage generated in the resistor generates and outputs data of the constant charging voltage of the battery, the Collecting respective data of a plurality of battery voltages and the constant charge voltage, and performing control to switch from constant current charge control to constant voltage charge control in the process of reaching full charge of the battery, and when the battery approaches full charge, A control step of detecting that the battery has reached the steady state normal charging current or less based on the voltage generated in the resistor and detecting the completion of charging of the battery, and charging in the process until the completion of charging of the battery according to the instruction of the control step. A battery charge detection control method is characterized by having a display step of displaying a state and notifying a user of an accurate charge state. The gist of the invention according to claim 7 is that the battery voltage detection circuit is a constant current charging control section.
The battery charge detection control method according to claim 6 , wherein the battery voltage is measured . The gist of the invention according to claim 8 is that the charging current detection step includes a voltage comparison step of setting a voltage value corresponding to each of the plurality of charging currents and the constant charging current to a threshold level, and the voltage comparison. 7. The battery charge detection control method according to claim 6, further comprising a step of detecting an output voltage from the charging current / voltage converting step in the step, and transmitting the detection result to the control step. The gist of the invention according to claim 9 is that, in the control step, data of each of the plurality of battery voltages generated and output by the battery voltage detection step, and the plurality of charges generated and output by the charging current detection step. 7. The method according to claim 6, further comprising the step of notifying the user of the state of charge during charging in the process up to completion of charging of the battery using the display step based on the current and the data of the constant charging current. The battery charge detection control method according to any one of 8 above. The gist of the invention according to claim 10 is that the control step of executing charge control of the battery comprises:
Wherein a constant current charging control in the constant current charging control section, switching to the constant voltage charging control at the end timing of the constant current charging control section reaching a constant voltage with the battery voltage, the determination that the fully charged at a constant charging current The battery charge detection control method according to any one of claims 6 to 9, further comprising the step of ending the charge control of the battery.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The features of the embodiments described below are as follows.
A charging circuit for performing constant voltage charging and / or constant current charging for the lithium ion battery, a resistor for generating a voltage according to the charging current of the lithium ion battery, and a constant voltage charging for the lithium ion battery. A battery voltage detection circuit that generates and outputs battery voltage data by detecting the voltage across the lithium-ion battery based on the voltage across the lithium-ion battery in the voltage charging control section, and a constant-current charging control section that performs constant-current charging of the lithium-ion battery. Charging that generates and outputs charging current and steady charging current data by detecting the charging current of the lithium-ion battery and the steady charging current that is a nearly constant charging current value near full charge based on the voltage generated in the resistor. By using the current detection circuit, it is possible to accurately read the charge state of the lithium ion battery during charging. In addition, data of the charging current, the steady charging current, and / or the battery voltage is collected, and the control for switching from the constant current charging control to the constant voltage charging control is performed while the lithium ion battery reaches the full charge. A control unit that detects the completion of charging of the lithium-ion battery by reading the voltage that occurs near the full charge and becomes less than the steady-state charging current based on the voltage generated in the resistor, and according to the instruction of the control unit, until the completion of charging of the lithium-ion battery By using the display unit that displays the charging status in the process and notifies the user of the accurate charging status,
It is to accurately display the state of charge on the display unit that displays the state of charge in the process up to completion of charging, and to notify the user of the accurate state of charge. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a functional block diagram for explaining a lithium ion battery charger 10 according to an embodiment of the present invention, and FIGS. 2A and 2B are lithium according to an embodiment of the present invention. The battery voltage characteristic curve Lv and the charging current characteristic curve Li for explaining the ion battery charge detection control method are shown, respectively. In FIG. 1, 1 is a charging circuit, 2 is a control unit, 3 is a lithium ion battery, 4 is a battery voltage detection circuit, 5 is a charging current detection circuit, 6 is a resistor, 7 is a display unit,
10 is a lithium ion battery charger, and in FIG. 2,
A, B, C, D are charge states, D1, D2, D3, D4 are charge states, ID1, ID2, ID3 are charge currents, ID4
Indicates a steady charging current, Li indicates a charging current characteristic curve, Lv indicates a battery voltage characteristic curve, and VA, VB and VC indicate battery voltages. Referring to FIG. 1, a lithium ion battery charger 10 according to the present embodiment includes a charging circuit 1, a control unit 2, a lithium ion battery 3, a battery voltage detection circuit 4, a charging current detection circuit 5, a resistor 6, and a display unit. Equipped with 7.

Referring to FIGS. 1 and 2, the charging circuit 1 performs constant voltage charging and / or constant current charging on the lithium ion battery 3. The resistor 6 is a lithium-ion battery 3
Generates a voltage according to the charging current of. The battery voltage detection circuit 4 detects the battery voltages VA to VC of the lithium-ion battery 3 based on the voltage across the lithium-ion battery 3 in the constant-voltage charging control section in which the lithium-ion battery 3 is charged at a constant voltage. It generates and outputs data of voltages VA to VC.
The charging current detection circuit 5 is a steady state which is the charging currents ID1 to ID3 of the lithium ion battery 3 during the constant current charging control section in which the constant current charging of the lithium ion battery 3 is performed, and a substantially constant charging current value near the full charge. The charging currents ID1 to ID4 are detected by detecting the charging current ID4 based on the voltage generated in the resistor 6.
3 and the data of the steady charging current ID4 is generated and output. The control unit 2 collects the data of the charging currents ID1 to ID3, the steady charging current ID4, and / or the battery voltages VA to VC, and controls the constant current charging control to the constant voltage charging control while the lithium ion battery 3 reaches the full charge. The control for switching to is performed, and the completion of charging of the lithium ion battery 3 is detected by reading that the lithium ion battery 3 approaches the full charge and becomes equal to or less than the steady charging current ID4 based on the voltage generated in the resistor 6. The display unit 7 displays the charging state of the lithium-ion battery 3 in the process until the charging is completed according to the instruction of the control unit 2 to notify the user of the accurate charging state.

The structure of the lithium ion battery charger 10 will be described in more detail. In the lithium ion battery charger 10 of the present embodiment, the charging circuit 1 and the control unit 2 control the constant voltage charging and / or the constant current charging to charge the lithium ion battery 3. The charging current at this time is converted into a voltage by the resistor 6 according to Ohm's law, and is output to the charging current detection circuit 5 as a voltage. Charge current detection circuit 5
Are charging currents ID1 to ID3 and steady charging current ID
4 is provided with a comparator for setting the voltage value corresponding to each of 4 to a threshold level, the comparator detects the output voltage from the resistor 6 and transmits the detection result to the control unit 2. The display unit 7 is an LED (light emitting diode) that can be turned on or blinks, or an LC.
Display means such as D (liquid crystal display) is provided.

The control unit 2 is generated by the battery voltage detection circuit 4.
Based on the data of the battery voltages VA to VC to be output, the charging currents ID1 to ID3 generated and output by the charging current detection circuit 5, and the data of the steady charging current ID4, the charging process of the lithium ion battery 3 in the process until the charging is completed. The charging state of the LED is turned on or blinked by the LED provided in the display unit 7, or the display unit such as LCD is used to notify (display) to the user, and processing such as wireless communication and call processing is performed. ing.

As shown in FIG. 2, the control unit 2 for controlling the charging of the lithium ion battery 3 first performs the constant current charging control in the constant current charging control section shown in FIG. At the end timing of the constant current charging control section where the battery voltage reaches a certain constant voltage, switching to the constant voltage charging control section (constant voltage charging control) shown in FIG.
The charging operation of terminating the charging control of the lithium-ion battery 3 when it is judged that the charging current is gradually reduced and the charging current is equal to or less than the charging current (that is, the steady charging current ID4 shown in FIG. Is configured to do.

Next, the operation of the lithium ion battery charger 10 (lithium ion battery charge detection control method) will be described with reference to FIGS. In the lithium-ion battery charger 10 having the hardware configuration as shown in FIG.
As shown in FIG. 2, in the constant current charge control section in which the battery voltage is less than a certain constant value, the charging circuit 1 performs constant current control based on the detection results of the resistor 6 and the charging current detection circuit 5. Further, when the battery voltage (> VC) for constant voltage charging control is reached, the charging circuit 1 and the control unit 2 perform control to gradually reduce the charging current.
It changes as shown in (b). When the charging current is below a certain charging current in the constant voltage charging control section, that is, when the voltage generated in the resistor 6 is below a certain voltage, the charging current detection circuit 5 detects that the voltage is below a certain voltage,
The result is transmitted to the control unit 2 by the information of "L level" and "H level".

In response to this, the control unit 2 confirms the battery voltage with the battery voltage detection circuit 4, and based on the battery voltage characteristic curve Lv shown in FIG. 2A, the charging states A, B, C during charging. , D
Judge each of. In the charging state D, based on the information sent from the charging current detection circuit 5 and the charging current characteristic curve Li shown in FIG. 2B, the charging states D1, D2, D
Each of 3 and D4 is judged.

The display unit 7 has, for example, a function capable of expressing several kinds of charging states by LEDs of several colors and a function capable of displaying the charging state by means of an expression such as "charging level 30%" on the LCD. As described above, the control unit 2 can accurately determine the charging state, and notify the user of the charging state during charging by means of the display unit 7 such as lighting or blinking of an LED or LCD display.

Conventionally, as a means for judging the state of charge of the battery, it is possible to grasp the state of charge to some extent by monitoring the battery voltage. However, the lithium ion battery 3 is fully charged when it reaches a certain charge level. Since there is almost no voltage change that is almost equal to the voltage at the time, the charge level near full charge becomes extremely long even if an accurate voltage detection circuit is used, and it is impossible to accurately notify the user of the charge level. It was possible. On the other hand, as described above, according to the present embodiment, the battery voltage of the lithium-ion battery 3 is monitored, and the information on the charging current is also used during the constant voltage charging control, so that the charging start state to the charging completion state can be changed. It becomes possible to judge the level of the charge state up to and evenly distributed, and as a result, it becomes possible to notify the user of the accurate level of the charge state.

The present invention is not limited to lithium ion batteries, but can be applied to general secondary batteries. Further, it is obvious that the present invention is not limited to the above-mentioned respective embodiments, and the respective embodiments can be appropriately changed within the scope of the technical idea of the present invention. Further, the number, positions, shapes, etc. of the above-mentioned constituent members are not limited to those in the above-mentioned embodiment, and the number, positions, shapes, etc. suitable for carrying out the present invention can be adopted. Also,
In each drawing, the same constituent elements are designated by the same reference numerals.

[0017]

Since the present invention is configured as described above, by monitoring the battery voltage of the battery and also using the information of the charging current during the constant voltage charging, the charging start state to the charging completion state can be obtained. It is possible to determine the state of charge of the battery with equal distribution, and as a result, it is possible to notify the user of the accurate level of the state of charge.

[Brief description of drawings]

FIG. 1 is a functional block diagram for explaining a lithium-ion battery charger according to an embodiment of the present invention.

2 (a) and 2 (b) show a battery voltage characteristic curve and a charging current characteristic curve, respectively, for explaining a lithium ion battery charge detection control method according to an embodiment of the present invention. .

[Explanation of symbols]

1 ... Charging circuit 2 ... Control unit 3 ... Lithium-ion battery 4 ... Battery voltage detection circuit 5 ... Charging current detection circuit 6 ... Resistor 7 ... Display 10 ... Lithium-ion battery charger A, B, C, D ... Charge state D1, D2, D3, D4 ... Charge state ID1, ID2, ID3 ... Charging current ID4: steady charging current Li ... Charge current characteristic curve Lv ... Battery voltage characteristic curve VA, VB, VC ... Battery voltage

Claims (10)

(57) [Claims] 1. A battery charger capable of notifying the level judgment and accurate state of charge level of the charge state from the charge start state until the charge completion state at even distribution to the user, the constant relative to the cell A charging circuit that performs current charging and constant voltage charging, a resistor that generates a voltage according to the charging current of the battery, and a constant voltage charging control section that performs constant voltage charging of the battery
A battery voltage detection circuit for generating and outputting each data of the plurality of battery voltage each of the plurality of battery voltage of the battery is detected based on the voltage across the battery during the constant voltage charging of the battery A charging current detection circuit that generates and outputs constant charging voltage data by detecting the charging current based on the voltage generated in the resistor during the constant voltage charging control period being performed, the plurality of battery voltages and the constant voltage. Collecting each data of the charging voltage, and performing control to switch from constant current charging control to constant voltage charging control in the process where the battery reaches full charge, and that the battery approaches full charge and falls below a constant charging current. A control unit that reads out based on the voltage generated in the resistor to detect the completion of charging of the battery, and displays a charge state in the process until the completion of charging of the battery according to an instruction from the control unit. Battery charger, characterized in that it comprises a display unit for notifying an accurate state of charge over THE. 2. The battery voltage detection circuit is a constant current charge control circuit.
The battery charger according to claim 1 , wherein the battery voltage is measured during the control section . 3. The charge current detection circuit includes a comparator that sets a voltage value corresponding to each of the plurality of charge currents and the constant charge current as a threshold level, and the comparator outputs an output voltage from the resistor. The battery charger according to claim 1, wherein the battery charger is configured to detect and transmit the detection result to the control unit. 4. The controller controls the battery voltage detection circuit to generate and output the respective battery voltage data, the charging current detection circuit to generate and output the charging currents, and the constant charge. 4. The display unit is configured to notify the user of the state of charge during charging in the process up to the completion of charging of the battery based on the current data, according to any one of claims 1 to 3. The battery charger according to 1 above. Wherein the control unit that executes charging control of the battery, the battery was treated with constant current charge control in the constant current charging control section, the constant current <br/> charging control section reaching a constant voltage that the battery voltage 5. It is configured to switch to constant voltage charging control at the end timing of, and to terminate the charging control of the battery when it is determined that the battery is fully charged by the constant charging current. The battery charger according to 1 above. 6. A battery charge detection control method capable of determining a level of a charge state from a charge start state to a charge complete state by even distribution and notifying a user of an accurate level of the charge state. A constant current charge and a constant voltage charge are performed, a charge current-voltage conversion step of generating a voltage according to the charge current of the battery using a resistor, and a constant voltage charge of the battery. A battery voltage detection step of detecting each of a plurality of battery voltages of the battery in the constant voltage charging control section based on the voltage across the battery and generating and outputting data of each of the plurality of battery voltages, A charging current detecting step of generating and outputting constant charging voltage data by detecting a charging current based on a voltage generated in the resistor during a constant voltage charging control section performing constant voltage charging, and the plurality of batteries. Voltage and The collect respective data of the constant charging voltage, and performs control for switching from constant current charging control in the process of the battery reaches a full charge to the constant voltage charging control, following the steady-state normal charging current the battery approaches full charge The control step of detecting that the battery has been charged based on the voltage generated in the resistor, and displaying the charge state in the process until the battery is completely charged according to the instruction of the control step. A battery charge detection control method comprising a display step of notifying a user of an accurate charge state. 7. The battery charge detection control method according to claim 6, wherein the battery voltage detection circuit measures the battery voltage during a constant current charge control period. 8. The charging current detecting step includes a voltage comparing step of setting a voltage value corresponding to each of the plurality of charging currents and the constant charging current to a threshold level, and the charging current voltage is set in the voltage comparing step. The battery charge detection control method according to claim 6, further comprising a step of detecting an output voltage from the conversion step and transmitting the detection result to the control step. 9. The control step includes data of each of the plurality of battery voltages generated and output by the battery voltage detection step, the plurality of charging currents generated and output by the charging current detection step, and the constant charge. 9. The method according to claim 6, further comprising the step of notifying a user of the state of charge during charging in the process until the battery is completely charged, using the display step, based on current data. The battery charge detection control method according to [4]. Said control step 10. executes charging control of the battery, the battery was treated with constant current charge control in the constant current charging control section, the constant reaching a constant voltage that the battery voltage
10. The method according to claim 6, further comprising the step of switching to constant voltage charging control at the end timing of the current charging control section, deciding that the battery is fully charged with the constant charging current, and ending the charging control of the battery. The battery charge detection control method according to any one of claims.