JP2017017932A - Charging method for secondary battery with additional function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging method which is capable of detecting full charge even if -Δ(delta)V cannot be detected, and is not influenced by noise of a motor or the like, in a charging method for a secondary battery comprising an additional function such as a fan or a light.SOLUTION: The charging method for the secondary battery includes: a secondary battery 3; a microcomputer 4 including a timer function; an additional function having a plurality of modes that are switched by a switching operation; an additional function circuit 5 which performs a mode change of the additional function; a charge control circuit 6 which controls output to the secondary battery; and a power supply switch circuit 2 which outputs power supply while distributing the same to the microcomputer or the charge control circuit. A threshold value A is set from data based on a charging voltage profile, and a secondary battery voltage of the secondary battery is measured to calculate a curve S of a voltage change at an interval of a predetermined time. If the curve S exceeds the threshold value A and then falls lower than the threshold value A, full charge is discriminated.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for charging a rechargeable battery having an additional function such as a fan or a light, and relates to a method for charging a rechargeable battery using a power source with a limited output current, such as a USB port.

  In many conventional charging methods for rechargeable batteries such as nickel metal hydride, the charging method of the-▲ △ ▼ (delta) V detection method is adopted, and the open-circuit voltage of the rechargeable battery is measured at a certain timing. It is determined whether the battery is fully charged. Many countermeasures against overcharging are also used in combination with a timer method for setting a maximum charging time.

  In addition, in the above-mentioned conventional rechargeable battery, the charge profile of the rechargeable battery, that is, a rechargeable battery data sheet such as a graph of charging time and voltage change, test result data of the rechargeable battery manufacturer, and further the nominal voltage of the rechargeable battery itself (For example, 3.6V, 4.8V, etc.) is given in advance.

JP-A-55-141938 JP 61-288740 A Japanese Patent Laid-Open No. 9-233729 JP 2001-186683 A JP 2007-252086 A JP 2012-23849 A Japanese Patent No. 3219731

  In such a charging method of a rechargeable battery having an additional function such as a fan or a light, the following problems occur when charging and the operation of the additional function, for example, the fan operation is performed simultaneously.

  When charging with a power source with a limited output current, such as a USB port, the current that can be used for charging is reduced due to the influence of the consumption current of the additional function, so that −ΔΔ (delta) V may not be detected.

  In addition, due to the noise of the motor that drives the additional function, the error in the measured value of the open-circuit voltage of the rechargeable battery becomes large, and thus there is a possibility of erroneous detection of full charge.

  The present invention has been made in view of the above circumstances, and uses the above-described rechargeable battery profile, charging manufacturer test result data, or the nominal voltage of the rechargeable battery (hereinafter referred to as “charging voltage profile”). Therefore, when using a power supply with limited output current, such as a USB port, the charging current becomes small due to the current consumption of the additional function, and even when − ▲ △ ▼ (delta) V cannot be detected, the battery is fully charged. The charging method that can be detected is proposed.

  Furthermore, the present invention proposes a charging method capable of charging without erroneous detection of full charge even under the influence of motor noise when charging and additional function operation are performed simultaneously in the additional function having a charging function. It is.

The present invention is a charging system that uses a power source with limited output current, such as a USB port, in a charging method for a rechargeable battery having an additional function such as a fan or a light.
A rechargeable battery;
A timer function that counts the elapsed time from the start of charging, a microcomputer that monitors and controls the voltage and power supply voltage of the rechargeable battery, and a charging current;
An additional function having a plurality of modes switched by a switching operation;
An additional function circuit for changing the mode of the additional function by the switching operation;
A charge control circuit for controlling output of the current from the power source to the rechargeable battery;
A power source switching circuit that selectively switches the current supplied from the power source and the rechargeable battery and distributes and outputs to the microcomputer or the charge control circuit;
With
From the data of charging time and battery voltage change based on the charging voltage profile in the rechargeable battery, or the measured value data of the charging time and battery voltage change in the rechargeable battery, the slope of the voltage change graph for each predetermined time is calculated. , A threshold A is set from the slope of the voltage in the vicinity estimated to be fully charged in the voltage change graph,
Measure the rechargeable battery voltage of the rechargeable battery, calculate the slope of the voltage change every predetermined time, and determine that this slope is fully charged when the threshold A is lowered after the threshold A is raised. It is the charging method of the rechargeable battery characterized.

  The invention described in claim 2 of the present application is the method of charging a rechargeable battery according to claim 1, wherein the slope is calculated based on a measured voltage obtained by calculating an average value for each fixed time.

  The conventional method of detecting-[Delta] (delta) V after full charge detects full charge by using a voltage drop caused by a chemical reaction due to overcharge. In a rechargeable battery having a voltage of −ΔΔ (delta) V cannot be detected because the charging current is reduced due to the influence of current consumption and the voltage drop due to the chemical reaction is very small.

  In this respect, the present application does not detect the full charge by detecting − ▲ Δ ▼ (delta) V, but measures the rechargeable battery voltage (open voltage) and determines the slope of voltage change (voltage The rate of increase is calculated to determine full charge.

  That is, even when −ΔΔ (delta) V cannot be detected after full charge, it is estimated that the battery is fully charged by paying attention to the slope of the voltage change (voltage increase rate) per predetermined time. Even if the voltage change of the open-circuit voltage of the rechargeable battery gradually increases in the vicinity, as shown in FIG. 1, the slope of this voltage change has a peak portion in the latter half of the slope graph. The threshold value is the difference between the slope value of the vertex P0 and the slope value of the vertex P0 (the difference between P0 and P1 in this example) that is larger at the points P1 and P2 that are T1 (elapsed time) away from the vertex P0 of the mountain Set to A. Here, the reason why the larger slope value (P1) is adopted is to shorten the overcharge state so as not to adversely affect the life of the rechargeable battery.

  Thus, from the data of the charging time and the battery voltage change based on the charging voltage profile in the rechargeable battery to be charged or the measured value data of the charging time and the battery voltage change in the rechargeable battery, A slope is calculated, and a threshold value A is set from the slope of the voltage in the vicinity where the voltage change graph is estimated to be fully charged.

  Then, when charging the rechargeable battery, the rechargeable battery voltage is measured, and the slope of the voltage change for each predetermined time is calculated. After the slope increases above the threshold A after P1, the threshold A is lowered. Sometimes it is determined that the battery is fully charged (when it descends from P0 and becomes less than or equal to P1).

  According to the present invention, even when charging is performed with a small charging current that does not allow detection of a full charge by detection of-[Delta] (delta) V due to the current consumption of the additional mechanism, the threshold A is used to fully charge the battery. Therefore, overcharging can be prevented.

  Furthermore, since the inclination is calculated based on the measured voltage obtained by calculating the average value for every predetermined time, the full charge can be charged without erroneous detection even under the influence of the noise of the motor.

  Moreover, since the timer function which counts the elapsed time from the start of charging is provided, when the elapsed charging time is equal to or longer than the maximum charging time, the charging can be terminated to avoid overcharging.

FIG. 5 is a graph for explaining the present invention, in which “elapsed time” is plotted on the horizontal axis, “rechargeable battery voltage” and “calculated slope value every T1 elapsed” are plotted on the vertical axis, It is the graph which showed the change of the inclination of the voltage change graph of a battery. It is a charge system block diagram concerning the Example of this invention. 4 is a flowchart illustrating a charging operation according to the embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing the configuration of the charging system of this example. In this example, the power source from the USB port of a power supply device such as a personal computer is used.

  The power supply of the USB port has a limited output current. For example, USB 2.0 supplies 5 V and 500 mA. In addition to USB 2.0, USB 3.0 (5 V, 900 mA) can also be used.

  As shown in FIG. 2, the charging system configuration 1 of this example includes a power supply switching circuit 2 connected to a USB port of a power supply device 100 with a USB cable, a rechargeable battery 3, a microcomputer 4 having a timer function, and additional functions (for example, An additional function circuit 5 that changes the mode of the fan), and a charge control circuit 6 that supplies the current output from the power supply switching circuit 2 to the rechargeable battery 3.

  The power supply switching circuit 2 selectively switches the current supplied from the USB power supply and the rechargeable battery 3 and distributes the current to the microcomputer 4 or the charge control circuit 6 for output.

  As the rechargeable battery 3, an appropriate battery such as a nickel metal hydride battery or a nickel cadmium battery is used.

  The microcomputer 4 has a timer function for counting the elapsed time from the start of charging, and monitors the voltage and power supply voltage (USB power supply) of the rechargeable battery 3 and controls and monitors the charging current.

  In the additional function circuit 5, the mode (ON / OFF, strong / weak, etc.) of the additional function is changed by, for example, an ON / OFF operation by a changeover switch or a switching operation of a plurality of modes such as strong / weak.

  As described above, the charging control circuit 6 supplies the current output from the power source switching circuit 2 to the rechargeable battery 3, and the output of the current is controlled by the microcomputer 4.

  In the charging system of the present example configured as described above, the additional function mode is confirmed, and the maximum charging time and the charging current maximum value are set. When the additional function mode is changed, the charging current maximum value is changed and the maximum charging time is switched based on the changed mode.

  This will be described below with reference to the flowchart shown in FIG.

  When a charging current is supplied from the USB power source and a charging operation is started, a threshold A is set in step 110. As described above, the threshold A is “data of charging time and battery voltage change” based on the charging voltage profile of the rechargeable battery, or “charge time and battery voltage change” measured in advance using the rechargeable battery. The slope of the voltage change graph for each predetermined time is calculated from the “measured value data”, and the threshold value A is set from the slope of the voltage in the vicinity estimated to be fully charged in the voltage change graph.

  In step 120, the timer starts to start measuring the charging time, and in step 130, measurement of the rechargeable battery voltage (open voltage) is started. This measurement is performed at intervals of 1 second, for example.

  In step 140, it is determined whether or not a predetermined time T1 has elapsed. Here, T1 is, for example, 10 seconds, and when 10 seconds have elapsed, the average value is calculated in step 150, and the T1 timer is restarted in step 160. When the predetermined time T1 has not elapsed in step 140, the process proceeds to step 200 described later.

After the T1 timer is restarted in step 160, it is determined in step 170 whether or not a predetermined time T2 has elapsed. Here, if T2 is 60 seconds, for example,
If YES in step 170, since there are six average values at this point, the slope S is calculated from these six average values in step 180. If NO in step 170, the process proceeds to step 200.

  When the slope S is calculated from the average value in step 180, it is determined in step 190 whether or not the slope S increases the threshold value A and then decreases A. If YES, the charging is terminated. If NO in step 190, the process proceeds to step 200.

  In step 200, it is determined whether the battery is in the maximum charge state. In this example, the elapsed charging time from the start of the timer in step 120 is calculated, and it is determined whether the elapsed charging time is equal to or longer than the maximum charging time. If YES in step 200, charging is terminated, while if NO in step 200, the process proceeds to step 130 and the above steps are repeated.

  In the flowchart described above, the average value is calculated in step 150 after the predetermined time T1 has elapsed in step 140, and the slope S is calculated in step 180 after the predetermined time T2 has elapsed in step 170. The slope S is calculated based on the measured voltage obtained by calculating the average value for every fixed time. Therefore, even under the influence of the motor noise, the full charge can be charged without erroneous detection.

  In this example, the timer function for counting the elapsed time from the start of charging is provided. Therefore, in step 200, when the elapsed charging time is equal to or longer than the maximum charging time, charging is terminated to avoid overcharging. Can do.

  In the above-described embodiments, the case where the power supply from the USB port of a power supply device such as a personal computer is used has been described as an example. However, the present invention is not limited to this, and a general power supply device with a limited output current is used. Can be used.

  Furthermore, the present invention is not limited to the additional functions used in the embodiments, and appropriate additional functions can be used. Also, the present invention can be applied to a mobile phone, a smartphone, or the like that uses other secondary batteries with additional functions. Is.

  It should be noted that the technical configuration according to the present invention is for the case where the charging current is small and it is difficult to detect −ΔΔ (delta) V without using an additional function (when a power supply device having a small output current is used). Therefore, the same full charge detection function is effective.

  The charging system of the present invention can be suitably used for a general charging system that uses a power source with limited output current, such as a USB port.

DESCRIPTION OF SYMBOLS 1 Charging system structure 2 Power supply switching circuit 3 Rechargeable battery 4 Microcomputer 5 Additional function circuit 6 Charge control circuit 100 Power supply device A Threshold value S Inclination

Claims (2)

In a charging system using a power source with limited output current, such as a USB port, for charging a rechargeable battery having an additional function such as a fan or a light,
A rechargeable battery;
A timer function that counts the elapsed time from the start of charging, a microcomputer that monitors and controls the voltage and power supply voltage of the rechargeable battery, and a charging current;
An additional function having a plurality of modes switched by a switching operation;
An additional function circuit for changing the mode of the additional function by the switching operation;
A charge control circuit for controlling output of the current from the power source to the rechargeable battery;
A power source switching circuit that selectively switches the current supplied from the power source and the rechargeable battery and distributes and outputs to the microcomputer or the charge control circuit;
With
From the data of charging time and battery voltage change based on the charging voltage profile in the rechargeable battery, or the measured value data of the charging time and battery voltage change in the rechargeable battery, the slope of the voltage change graph for each predetermined time is calculated. , A threshold A is set from the slope of the voltage in the vicinity estimated to be fully charged in the voltage change graph,
Measure the rechargeable battery voltage of the rechargeable battery, calculate the slope of the voltage change every predetermined time, and determine that this slope is fully charged when the threshold A is lowered after the threshold A is raised. A charging method for a rechargeable battery. 2. The method for charging a rechargeable battery according to claim 1, wherein the inclination is calculated based on a measured voltage obtained by calculating an average value for each predetermined time.

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